Lexical Definition

‎εὐχή‎ euchḗ (yoo-khay') a vow/prayer ^G:N-F
from ‎εὔχομαι‎

prayer, vow.

• properly, a wish, expressed as a petition to God, or in votive obligation

Abbott-Smith

εὐχή, -ῆς, ἡ (< εὔχομαι), [in LXX chiefly for נֵדֶר ;]
1. a prayer: Ja 5:15.
2. a vow: Ac 18:18 21:23.†
SYN.: v.s. δέησις

Abbott-Smith References

Liddell-Scott-Jones

εὐχή, ἡ,

(εὔχομαι) prayer or vow, once in [Refs 8th c.BC+]; εὐχὴν ἐπιτελέσαι, Latin vota persolvere, [Refs 5th c.BC+]; εὐχῇ χρῆσθαι, Latin votis potiri, [Refs 5th c.BC+]; κατὰ χιλίων.. εὐχὴν ποιήσασθαι χιμάρων to make a vow of a thousand goats, [Refs 5th c.BC+]; εὐχὰς ποιεῖσθαι [Refs 5th c.BC+]; κατ᾽ εὐχήν, ἐξ εὐχῆς, Latin ex voto, [Refs 3rd c.BC+]; ἔχειν εὐχήν to be under a vow, [NT]

__2 wish or aspiration, opposed to reality, εὐχαῖς ὅμοια λέγειν to build 'castles in the air', [Refs 5th c.BC+]; κατὰ τὴν τῶν παίδων εὐ. like a boy's wish, [Refs]; εὐχῆς ἄξια things to be wished, but not expected, [Refs 5th c.BC+]; πολιτεία ἡ κατ᾽ εὐχὴν γινομένη the ideal state, [εὐχήν [prev. work] 1260b29. ">Refs 4th c.BC+]
__3 prayer for evil, i.e. curse, imprecation, πατρὸς κατ᾽ εὐχάς [Refs 5th c.BC+]

_{LSJ Scripture Refs: Acts.18.18}