Quick Definition
I prop up, uphold, confirm
Strong's Definition
to support further, i.e. reestablish
Derivation: from G1909 (ἐπί) and G4741 (στηρίζω);
KJV Usage: confirm, strengthen
Thayer's Greek Lexicon
ἐπιστηρίζω; 1 aorist ἐπεστηριξα; a later word; to establish besides, strengthen more; to render more firm, confirm: τινα, one's Christian faith, Act_14:22; Act_15:32; Act_15:41; Act_18:23 R G.
Mounce Concise Greek Dictionary
ἐπιστηρίζω epistērizō 4x
pr. to cause to rest or lean on, to settle upon; met. to conform, strengthen, establish, Act_14:22 ; Act_15:32 ; Act_15:41 ; Act_18:23
Abbott-Smith Greek Lexicon
ἐπι -στηρίζω ,
[in LXX for H5564 , etc.;]
to make stronger, confirm: c . acc , Act_14:22 ; Act_15:32 ; Act_15:41 .†
Liddell-Scott — Intermediate Greek Lexicon
ἐπιστηρίζω fut. ξω "to make to lean on":—Pass. "to lean upon", τινι Luc.
STEPBible — Tyndale Abridged Greek Lexicon
ἐπι-στηρίζω
[in LXX for סָמַךְ, etc. ;]
to make stronger, confirm: with accusative, Act.14:22 15:32, 41.†
(AS)