Quick Definition
I strengthen, confirm, establish
Strong's Definition
to solidify, i.e. confirm (literally or figuratively)
Derivation: from G4731 (στερεός);
KJV Usage: establish, receive strength, make strong
Thayer's Greek Lexicon
στερεόω, στερέω: 1 aorist ἐστερέωσα; imperfect 3 person plural ἐστερεοῦντο; 1 aorist passive ἐστερεωθην; (στερεός); to make solid, make firm, strengthen, make strong: τινα, the body of anyone, Act_3:16; τάς βάσεις, passive, Act_3:7; passive, τῇ πίστει, as respects faith (see στερεός, at the end), Act_16:5. (The Sept.; Xenophon, Diodorus.)
Mounce Concise Greek Dictionary
στερεόω stereoō 3x
to make firm; to strengthen, Act_3:7 ; Act_3:16 ; to settle, Act_16:5
Abbott-Smith Greek Lexicon
στερεόω , -ῶ
( < στερεός ),
[in LXX : Isa_42:5 ( H7554 ), Jer_5:3 ( H2388 pi .), etc.;]
(a) to make firm or solid;
(b) to strengthen, make strong; c . acc pers ., Act_3:16 ; τ . βάσεις ,, pass ., Act_3:7 . Metaph . ( cf. Je, l.c .): τ . πίστει ,, pass ., Act_16:5 .†
Moulton & Milligan — Vocabulary of the Greek NT
στερεόω [page 588]
make firm ( Act_3:16 ) : cf. Alex. Trall. II. p. 583 Putschm. (12th book), where as a charm against gout the sufferer is to write certain magic words on a gold leaf, and to add ὡς στερεοῦται ὁ ἥλιος ἐν τοῖς ὀνόμασι τούτοις καὶ ἀνακαινίζεται καθ᾽ ἑκάστην ἡμέραν , οὕτω στερεώσατε τὸ πλάσμα τοῦτο . . . (the passage is cited in P Osl I. p. 88).
Liddell-Scott — Intermediate Greek Lexicon
στερεόω στερεόω, φυτ. -ώσω "to make firm or solid", Xen. :— "to strengthen", NTest. :—Pass. "to be made strong", Xen.
STEPBible — Tyndale Abridged Greek Lexicon
στερεόω, -ῶ
(στερεός), [in LXX: Isa.42:5 (רָקַע), Jer.5:3 (חָזַק pi.), etc. ;]
__(a) to make firm or solid;
__(b) to strengthen, make strong; with accusative of person(s), Act.3:16; τ. βάσεις, pass., Act.3:7. Metaphorical (cf. Je, l.with): τ. πίστει, pass., Act.16:5.†
(AS)