Here's BDAG...
βαπτίζω fut. βαπτίσω; 1 aor. ἐβάπτισα. Mid.: ἐβαπτισάμην. Pass.: impf. ἐβαπτιζόμην; fut. βαπτισθήσομαι; 1 aor. ἐβαπτίσθην; pf. ptc. βεβαπτισμένος (Hippocr., Pla., esp. Polyb.+; UPZ 70, 13 [152/151 B.C.]; PGM 5, 69; LXX; ApcSed 14:7 [p. 136, 8f Ja.]; Philo; Joseph.; SibOr 5, 478; Just.; Mel., Fgm. 8, 1 and 2 Goodsp.=8b, 4 and 14 P.—In Gk. lit. gener. to put or go under water in a variety of senses, also fig., e.g. ‘soak’ Pla., Symp. 176b in wine) in our lit. only in ritual or ceremonial sense (as Plut.; Herm. Wr. [s. 2a below]; PGM 4, 44; 7, 441 λουσάμενος κ. βαπτισάμενος; 4 Km 5:14; Sir 34:25; Jdth 12:7; cp. Iren. 1, 21, 3 [Harv. I 183, 83]).
1. wash ceremonially for purpose of purification, wash, purify, of a broad range of repeated ritual washing rooted in Israelite tradition (cp. Just., D. 46, 2) Mk 7:4; Lk 11:38; Ox 840, 15.—WBrandt, Jüd. Reinheitslehre u. ihre Beschreibg. in den Ev. 1910; ABüchler, The Law of Purification in Mk 7:1–23: ET 21, 1910, 34–40; JDöller, D. Reinheits-u. Speisegesetze d. ATs 1917; JJeremias, TZ 5, ’49, 418–28. See 1QS 5:8–23; 2:25–3:12; 4:20–22.
2. to use water in a rite for purpose of renewing or establishing a relationship w. God, plunge, dip, wash, baptize. The transliteration ‘baptize’ signifies the ceremonial character that NT narratives accord such cleansing, but the need of qualifying statements or contextual coloring in the documents indicates that the term β. was not nearly so technical as the transliteration suggests.
2a. of dedicatory cleansing associated w. the ministry of John the Baptist (Orig., C. Cels. 1, 47, 4), abs. J 1:25, 28; 3:23a; 10:40; hence John is called ὁ βαπτίζων Mk 1:4; 6:14, 24 (Goodsp., Probs. 50–52).—Pass. Mt 3:16; ISm 1:1; oft. have oneself baptized, get baptized Mt 3:13f; Lk 3:7, 12, 21; 7:30; J 3:23b; GEb 18, 35f; IEph 18:2 al. (B-D-F §314; s. §317).—(ἐν) ὕδατι w. water Mk 1:8a; Lk 3:16a; Ac 1:5a; 11:16a; ἐν (τῷ) ὕδατι J 1:26, 31, 33; ἐν τῷ Ἰορδ. (4 Km 5:14) Mt 3:6; Mk 1:5; εἰς τὸν Ἰορδ. (cp. Plut., Mor. 166a βάπτισον σεαυτὸν εἰς θάλασσαν; Herm. Wr. 4, 4 βάπτισον σεαυτὸν εἰς τὸν κρατῆρα) Mk 1:9.—W. the external element and purpose given ἐν ὕδατι εἰς μετάνοιαν Mt 3:11a (AOliver, Is β. used w. ἐν and the Instrumental?: RevExp 35, ’38, 190–97).—βαπτίζεσθαι τὸ βάπτισμα Ἰωάννου undergo John’s baptism Lk 7:29. εἰς τί ἐβαπτίσθητε; Ac 19:3 means, as the answer shows, in reference to what (baptism) were you baptized? i.e. what kind of baptism did you receive (as the context indicates, John’s baptism was designed to implement repentance as a necessary stage for the reception of Jesus; with the arrival of Jesus the next stage was the receipt of the Holy Spirit in connection with apostolic baptism in the name of Jesus, who was no longer the ‘coming one’, but the arrived ‘Lord’)? β. βάπτισμα μετανοίας administer a repentance baptism vs. 4; GEb 13, 74.—S. the lit. on Ἰωάν(ν)ης 1, and on the baptism of Jesus by John: JBornemann, D. Taufe Christi durch Joh. 1896; HUsener, D. Weihnachtsfest2 1911; DVölter, D. Taufe Jesu durch Joh.: NThT 6, 1917, 53–76; WBundy, The Meaning of Jesus’ Baptism: JR 7, 1927, 56–75; MJacobus, Zur Taufe Jesu bei Mt 3:14, 15: NKZ 40, 1929, 44–53; SHirsch, Taufe, Versuchung u. Verklärung Jesu ’32; DPlooij, The Baptism of Jesus: RHarris Festschr. (Amicitiae Corolla), ed. HWood ’33, 239–52; JKosnetter, D. Taufe Jesu ’36; HRowley, TManson memorial vol., ed. Higgins ’59, 218–29 (Qumran); JSchneider, Der historische Jesus u. d. kerygmatische Christus ’61, 530–42; HKraft, TZ 17, ’61, 399–412 (Joel); FLentzen-Dies, D. Taufe Jesu nach den Synoptikern, ’70. More reff. s.v. περιστερά.
2b. of cleansing performed by Jesus J 3:22, 26; 4:1; difft. 4:2 with disclaimer of baptismal activity by Jesus personally.
2c. of the Christian sacrament of initiation after Jesus’ death (freq. pass.; s. above 2a; Iren. 3, 12, 9 [Harv. II 63, 3]) Mk 16:16; Ac 2:41; 8:12f, 36, 38; 9:18; 10:47; 16:15, 33; 18:8; 22:16; 1 Cor 1:14–17; D 7 (where baptism by pouring is allowed in cases of necessity); ISm 8:2.—β. τινὰ εἰς (τὸ) ὄνομά τινος (s. ὄνομα 1dγב) baptize in or w. respect to the name of someone: (τοῦ) κυρίου Ac 8:16; 19:5; D 9:5; Hv 3, 7, 3. Cp. 1 Cor 1:13, 15. εἰς τ. ὄν. τ. πατρὸς καὶ τ. υἱοῦ καὶ τ. ἁγίου πνεύματος Mt 28:19 (on the original form of the baptismal formula see FConybeare, ZNW 2, 1901, 275–88; ERiggenbach, BFCT VII/1, 1903; VIII/4, 1904; HHoltzmann, Ntl. Theologie2 I 1911, 449f; OMoe: RSeeberg Festschr. 1929, I 179–96; GOngaro, Biblica 19, ’38, 267–79; GBraumann, Vorpaulinische christl. Taufverkündigung bei Paulus ’62); D 7:1, 4. Likew. ἐν τῷ ὀν. Ἰ. Χριστοῦ Ac 2:38 v.l.; 10:48; ἐπὶ τῷ ὀν. Ἰ. Χρ. Ac 2:38 text; more briefly εἰς Χριστόν Gal 3:27; Ro 6:3a. To be baptized εἰς Χρ. is for Paul an involvement in Christ’s death and its implications for the believer εἰς τὸν θάνατον αὐτοῦ ἐβαπτίσθημεν vs. 3b (s. Ltzm. ad loc.; HSchlier, EvTh ’38, 335–47; GWagner, D. relgeschichtliche Problem von Rö 6:1–11, ’62, tr. Pauline Bapt. and the Pagan Mysteries, by JSmith, ’67; RSchnackenburg, Baptism in the Thought of St. Paul ’64, tr. of D. Heilsgeschehen b. d. Taufe nach dem Ap. Paulus ’50). The effect of baptism is to bring all those baptized εἰς ἓν σῶμα 1 Cor 12:13 (perh. wordplay: ‘plunged into one body’).—W. the purpose given εἰς ἄφεσιν τ. ἁμαρτιῶν Ac 2:38 (IScheftelowitz, D. Sündentilgung durch Wasser: ARW 17, 1914, 353–412).—Diod S 5, 49, 6: many believe that by being received into the mysteries by the rites (τελεταί) they become more devout, more just, and better in every way.—ὑπὲρ τ. νεκρῶν 1 Cor 15:29a, s. also vs. *29b, is obscure because of our limited knowledge of a practice that was evidently obvious to the recipients of Paul’s letter; it has been interpr. (1) in place of the dead, i.e. vicariously; (2) for the benefit of the dead, in var. senses; (3) locally, over (the graves of) the dead; (4) on account of the dead, infl. by their good ex.; of these the last two are the least probable. See comm. and HPreisker, ZNW 23, 1924, 298–304; JZingerle, Heiliges Recht: JÖAI 23, 1926; Rtzst., Taufe 43f; AMarmorstein, ZNW 30, ’31, 277–85; AOliver, RevExp 34, ’37, 48–53; three articles: Kirchenblatt 98, ’42 and six: ET 54, ’43; 55, ’44; MRaeder, ZNW 46, ’56, 258–60; BFoschini, 5 articles: CBQ 12, ’50 and 13, ’51.—On the substitution of a ceremony by another person cp. Diod S 4, 24, 5: the boys who do not perform the customary sacrifices lose their voices and become as dead persons in the sacred precinct. When someone takes a vow to make the sacrifice for them, their trouble disappears at once.
3. to cause someone to have an extraordinary experience akin to an initiatory water-rite, to plunge, baptize. Cp. ‘take the plunge’ and s. OED ‘Plunge’ II 5 esp. for the rendering of usage 3c, below.
3a. typologically of Israel’s passage through the Red Sea εἰς τὸν Μωϋσῆν ἐβαπτίσαντο they got themselves plunged/ baptized for Moses, thereby affirming his leadership 1 Cor 10:2 v.l. (if the pass. ἐβαπτίσθησαν is to be read with N. the point remains the same; but the mid. form puts the onus, as indicated by the context, on the Israelites).
3b. of the Holy Spirit (fire) β. τινὰ (ἐν) πνεύματι ἁγίῳ Mk 1:8 (v.l. + ἐν); J 1:33; Ac 1:5b; 11:16b; cp. 1 Cor 12:13 (cp. Just., D. 29, 1). ἐν πν. ἁγ. καὶ πυρί Mt 3:11b; Lk 3:16b (JDunn, NovT 14, ’72, 81–92). On the oxymoron of baptism w. fire: REisler, Orphischdionysische Mysterienged. in d. christl. Antike: Vortr. d. Bibl. Warburg II/2, 1925, 139ff; CEdsman, Le baptême de feu (ASNU 9) ’40. JATRobinson, The Baptism of John and Qumran, HTR 50, ’57, 175–91; cp. 1QS 4:20f.
3c. of martyrdom (s. the fig. uses in UPZ 70, 13 [152/151 B.C.]; Diod S 1, 73, 6; Plut., Galba 1062 [21, 3] ὀφλήμασι βεβ. ‘overwhelmed by debts’; Chariton 2, 4, 4, βαπτιζόμενος ὑπὸ τ. ἐπιθυμίας; Vi. Aesopi I c. 21 p. 278, 4 λύπῃ βαπτιζόμενος; Achilles Tat. 3, 10, 1 πλήθει βαπτισθῆναι κακῶν; Herm. Wr. 4, 4 ἐβαπτίσαντο τοῦ νοός; Is 21:4; Jos., Bell. 4, 137 ἐβάπτισεν τ. πόλιν ‘he drowned the city in misery’) δύνασθε τὸ βάπτισμα ὸ̔ ἐγὼ βαπτίζομαι βαπτισθῆναι; Mk 10:38 (perh. the stark metaph. of impending personal disaster is to be rendered, ‘are you prepared to be drowned the way I’m going to be drowned?’); cp. vs. 39; Mt 20:22 v.l.; in striking contrast to fire Lk 12:50 (GDelling, Novum Testamentum 2, ’57, 92–115).—PAlthaus, Senior, D. Heilsbedeutung d. Taufe im NT 1897; WHeitmüller, Im Namen Jesu 1903, Taufe u. Abendmahl b. Paulus 1903, Taufe u. Abendmahl im Urchristentum 1911; FRendtorff, D. Taufe im Urchristentum 1905; HWindisch, Taufe u. Sünde im ältesten Christentum 1908; ASeeberg, D. Taufe im NT2 1913; AvStromberg, Studien zu Theorie u. Praxis der Taufe 1913; GottfrKittel, D. Wirkungen d. chr. Wassertaufe nach d. NT: StKr 87, 1914, 25ff; WKoch, D. Taufe im NT3 1921; JLeipoldt, D. urchr. Taufe im Lichte der Relgesch. 1928; RReitzenstein, D. Vorgesch. d. christl. Taufe 1929 (against him HSchaeder, Gnomon 5, 1929, 353–70, answered by Rtzst., ARW 27, 1929, 241–77); FDölger, Ac I 1929, II 1930; HvSoden, Sakrament u. Ethik bei Pls: ROtto Festschr., Marburger Theologische Studien ’31, no. 1, 1–40; MEnslin, Crozer Quarterly 8, ’31, 47–67; BBacon, ATR 13, ’31, 155–74; CBowen: RHutcheon, Studies in NT, ’36, 30–48; GBornkamm, ThBl 17, ’38, 42–52; 18, ’39, 233–42; HSchlier, EvTh ’38, 335–47 (Ro 6); EBruston, La notion bibl. du baptême: ÉTLR ’38, 67–93; 135–50; HMarsh, The Origin and Signif. of the NT Baptism ’41; KBarth, D. kirchl. Lehre v. d. Taufe2 ’43 (Eng. tr., The Teaching of the Church Regarding Baptism, EPayne ’48); FGrant, ATR 27, ’45, 253–63; HSchlier, D. kirchl. Lehre v. d. Taufe: TLZ 72, ’47, 321–26; OCullmann, Baptism in the NT (tr. JReid) ’50; MBarth, D. Taufe ein Sakrament? ’51; RBultmann, Theology of the NT, tr. KGrobel ’51, I 133–44; JSchneider, D. Taufe im NT ’52; DStanley, TS 18, ’57, 169–215; EFascher, Taufe: Pauly-W. 2. Reihe IV 2501–18 (’32); AOepke, TW I ’33, 527–44; GBeasley-Murray, Baptism in the NT ’62; MQuesnel, Baptisés dans l’Esprit ’85 (Acts); DDaube, The NT and Rabbinic Judaism ’56, 106–40; NMcEleney, Conversion, Circumstance and the Law: NTS 20, ’74, 319–41; HBraun, Qumran u. d. NT II ’66, 1–29; OBetz, D. Proselytentaufe der Qumransekte u. d. NT: RevQ 1, ’58, 213–34; JYsebaert, Gk. Baptismal Terminology, ’62. S. τέκνον 1aα.—B. 1482. DELG s.v. βάπτω. M-M. EDNT. TW. Sv.
βάπτισμα, ατος, τό (s. βαπτίζω; found only in Christian writers; ApcSed 14:6 [p. 136, 7 and 9 Ja.]; Just., D.; Mel., Fgm. 6 al.)
1. the ceremonious use of water for purpose of renewing or establishing a relationship w. God, plunging, dipping, washing, water-rite, baptism
1a. of John’s rite (Orig., C. Cels. 1, 44, 13 al. [T. Jesus]) Mt 3:7; 21:25; Mk 11:30; Lk 7:29; 20:4; Ac 1:22; 10:37; 18:25; 19:3; β. μετανοίας Mk 1:4; Lk 3:3 (in these two passages with εἰς ἄφεσιν ἁμαρτιῶν [proclaiming] a baptism-with-repentance to receive forgiveness of sins) Ac 13:24; 19:4; GEb 13, 74.
1b. of Christian rite β. φέρον ἄφεσιν ἁμαρτιῶν B 11:1; β. εἰς τὸν θάνατον Ro 6:4 (s. βαπτίζω 2b). ἓν β. Eph 4:5. The person baptized is at the same time buried w. Christ Col 2:12 v.l.; 1 Pt 3:21 (s. ἀντίτυπος). Compared to a soldier’s weapons IPol 6:2. τηρεῖν τὸ β. ἁγνὸν καὶ ἀμίαντον 2 Cl 6:9. Ritual directions D 7:1, 4.
2. an extraordinary experience akin to an initiatory purification rite, a plunge, a baptism.
2a. metaph. of martyrdom Mk 10:38f; Lk 12:50; Mt 20:22f v.l. (s. GDelling, NovT 2, ’58, 92–115, and βαπτίζω 3c).
2b. metaph. of salvation β. ἐν σωτηρίᾳ Ἀχερουσίας λίμνης b. in the saving waters of the Acherusian lake ApcPt Rainer 1, 4f (s. Ἀχερούσιος; EPeterson, Frühkirche, Judentum u. Gnosis ’59, 310ff).—M-M. TW.
βαπτισμός, οῦ, ὁ (s. βαπτίζω; Antyllus the physician [II A.D.] in Oribasius 10, 3, 9, ‘act of immersion or dipping’)
1. water-rite for purpose of purification, washing, cleansing, of dishes Mk 7:4, 8 v.l. Of other ritual washings (Jos., Ant. 18, 117 of John’s baptism) Hb 9:10.—ESanders, Jewish Law fr. Jesus to the Mishnah ’90, 258–71 ( purification).
2. water-rite for purpose of renewing or establishing a relationship w. God, plunging experience, baptism burial with Christ in baptism Col 2:12. βαπτισμῶν διδαχή Hb 6:2 (a ref. to various water-rites, including prob. John’s baptism and Christian baptism).—M-M. TW.
Arndt, W., Danker, F. W., & Bauer, W. (2000). A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed.) (164–165). Chicago: University of Chicago Press.