Quick Definition
πληθύνω v. I increase, multiply
Strong's Definition
from another form of 4128; to increase (transitively or intransitively)
KJV Usage: abound, multiply
UBS Dictionary of the Greek New Testament
verb | πίμπλημι
59.68 · Quantity · Increase, Decrease
to grow, to increase greatly, to multiply to increase greatly in number or extent It may be difficult to speak of ‘a number growing’ in some languages, so that one may need to translate this expression in ACT 6:7 as ‘the disciples in Jerusalem became more and more’ or ‘there were more and more disciples in Jerusalem.’
It may be difficult, if not impossible, to speak of ‘evil increasing’ as in MAT 24:12, but one can usually speak of a greater number of instances of doing evil, and therefore one may translate ‘more and more people will be doing what is evil.’
A literal rendering of ACT 12:24 may be impossible in many languages, for a strictly literal rendering would imply that somehow the message from God ‘got bigger,’ which may mean in some languages ‘resulted in lies.’ The meaning is, of course, that more and more people accepted God’s word as true.
MAT 24:12 · ACT 6:1 · ACT 6:7 · ACT 7:17 · ACT 9:31 · ACT 12:24 · 1PE 1:2 · 2PE 1:2 · JUD 1:2
59.69 · Quantity · Increase, Decrease
to increase, to cause an increase, to multiply to cause an increase in the number of objects In HEB 6:14 it is essential in most languages to specify what is increased. A strictly literal translation such as ‘to cause you to increase’ would simply mean ‘to cause you to get big.’ The reference is clearly to Abraham’s descendants, and it is usually essential to make this reference clear.
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
πληθύνω ; fut. πληθυνῶ; 1 aor. opt. 3 pers. sing. πληθύναι (2 Co. ix. 10 Rec.); Pass., impf. ἐπληθυνόμην; 1 aor. ἐπληθύνθην; (fr. πληθύς fulness); Aeschyl., Aristot., Hdian., Geop.; Sept. very often for 739, 735, 7277, sometimes for 237; 1. trans. to increase, to multiply: 2 Co. ix. 10; Heb. vi. 14 (fr. Gen. xxii. 17); pass. to be increased, (be multiplied) multiply: Mt. xxiv. 12; Acts vi. 7; vii. 17; ix. 31; xii. 24; τινί, [A. V.be multiplied to one i. 6. be richly allotted to, 1 Pet. i. 2; 2 Pet. i. 2; Jude 2, (Dan. iii. 31 (98); Dan. vi. 25 Theodot. ; Clem. Rom. 1 Cor. 1 inser. [also Mart. Polye. inser. Constt. Apost. inser.]). 2. intrans. to be increased, to multiply: Acts vi. 1.
Mounce Concise Greek Dictionary
πληθύνω plēthunō 12x
optative, πληθύναι (3 sg), trans. to multiply, cause to increase, augment, 2 Cor. 9:10; Heb. 6:14; pass. to be multiplied, increase, be accumulated, Mt. 24:12; Acts 6:7; 7:17; intrans. to multiply, increase, be augmented, Acts 6:1
Abbott-Smith Greek Lexicon
πληθύνω
(causal of πληθύω, to be full, < πληθύς, Ion. for πλῆθος), [in LXX chiefly for רבה hi.;]
trans., to increase, multiply: II Co 9:10, He 6:14(LXX); pass., to be increased, to multiply: Mt 24:12, Ac 6:7 7:17 9:31 12:24; c. dat. pers. (Da LXX TH 3:31 (98) al.), I Pe 1:2, II Pe 1:2, Ju 2.
Intrans., to be increased, to multiply: Ac 6:1.†
Moulton & Milligan — Vocabulary of the Greek NT
πληθύνω, “‘increase,’’ ‘‘multiply ᾿ : cf. Pozmandres 3° (ed. Parthey) εἰς τὸ αὐξάνεσθαι ἐν αὐξήσει Kal πληθύνεσθαι ἐν πλήθει (cited by Dibelius HZNV7 ad Col 219). The verb is fully illustrated in Anz Sudsidia, p. 296 f.
Liddell-Scott-Jones — Greek-English Lexicon
πληθύνω (plēthunō) — to multiply. πληθ-ύνω, future -ῠνῶ[NT]: aorist ἐπλήθυνα [Refs 5th c.AD+] —causal of πληθύω, increase, multiply, [LXX+1st c.AD+]:—passive, ταῖς γυναιξὶ τὸ γάλα πληθύνεται abounds, [Refs 4th c.BC+]
2. make multiple, 'plurify', κατὰ ἀναλογίαν [τὸ ἡνωμένον] ἐπληθύναμεν τῶν κατωτέρω πεπληθυσμένων τὸν πρῶτον πληθυσμόν Dam.[same place]; θεοὶ -όμενοι μὲν ἐν τῷ κόσμῳ, περὶ αὐτὸν δὲ ἑνοειδῶς ὄντες [Refs 4th c.AD+]
3. intransitive, see at {πληθύω} [Refs]
4. use the plural, [Refs 8th c.BC+]
II. passive, to be in the majority, prevail, δήμου.. χεὶρ ὅπῃ πληθύνεται (codex middle πληθύεται) [Refs 4th c.BC+]infinitive, ταύτην ἐπαινεῖν.. πληθύνομαι I follow the majority, [Refs]: perfect πεπλήθυνται [LXX]
II.2. Grammars, [τὸ ἀπαρέμφατον] οὐ πληθύνεται the infinitive has no plural, [Refs 2nd c.AD+]