LSJ Gloss:ἐπιστροφήa turning about, twistingDodson:ἐπιστροφήa turning to Goda turning (to God), conversion.
Strong's:ἐπιστροφή reversion, i.e. morally, revolutionDerivation: from G1994;KJV Usage: conversion. G1994
TBESG:ἐπιστροφήconversionG:N-F ἐπι-στροφή, -ῆς, ἡ (ἐπιστρέφω) [in LXX: Eze.47:7 (שׁוּב), Refs Sir.18:21 49:2, etc. ;] a turning about; metaph., conversion (Field, Notes, 246): Act.15:3.† (AS)
ἐπιστροφή epistrophē ep-is-trof-ay' From G1994; reversion, that is, moral revolutionKJV Usage: conversion.
ἐπιστρέφω epistrephō ep-ee-stref'-o From G1909 and G4762; to revert (literally, figuratively or morally)KJV Usage: come (go) again, convert, (re-) turn (about, again).