Quick Definition
ἀδελφή, ῆς, ἡ n.f. a sister
Strong's Definition
fem of 80; a sister (naturally or ecclesiastically)
KJV Usage: sister
UBS Dictionary of the Greek New Testament
noun, f. | -ῆς | ἀδελφός
10.50 · Kinship Terms · Kinship Relations of the Same Generation
sister a female having the same father and mother as the reference person For a discussion of ἀδελφή[a] in the possible meaning of cousin, see the discussion under ἀδελφός[a] (10.49).
A number of languages make a distinction in relative age of sisters, paralleling the usage of distinct terms for ‘brother’ (see 10.49). The order of names in the NT normally suggests relative age, and therefore in speaking of Martha and Mary in such languages, one may designate Mary as the younger sister, since the order is normally first Martha and then Mary, though in JHN 11:1 the order is reversed.
MAT 12:50 · MAT 13:56 · MAT 19:29 · MRK 3:35 · MRK 6:3 · MRK 10:29 · MRK 10:30 · LUK 10:39 · LUK 10:40 · LUK 14:26 · JHN 11:1 · JHN 11:3 · JHN 11:5 · JHN 11:28 · JHN 11:39 · JHN 19:25 · ACT 23:16 · ROM 16:15 · 1TI 5:2 · 2JN 1:13
11.24 · Groups and Classes of Persons and Members of Such Groups and Classes · Socio-Religious
fellow believer, sister in Christ, sister in the faith a close female associate of a group with well-defined membership (in the NT referring specifically to fellow believers in Christ) Though in a number of languages it is possible to use a term meaning ‘sister’ in the sense of a fellow believer, in some languages this cannot be done. As in the case of ἀδελφός[b] (see 11.23), it may be possible to use a term such as ‘relative,’ but more often than not, it may be necessary to use a phrase such as ‘one who also believes’ or ‘one who believes in Christ even as we do.’
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
ἀδελφή, -ῆς, ἡ. (see ἀδελφός), [fr. Aeschyl. down], sister ; 1. a full, own sister (i.e. by birth): Mt. xix. 29; Lk. x. 39 sq.; Jn. xi. 1, 3, 5; xix. 25; Ro. xvi. 15, ete.; respecting the sisters of Christ, mentioned in Mt. xiii. 56; Mk. vi. 3, see ἀδελφός, 1. 2. one connected by the tie of the Christian religion: 1 Co. vii. 153; ix. 5; Philem. 2 L'T Tr WH; Jas. ii. 15; with a subj. gen., a Christian woman especially dear to one, Ro. xvi. 1.
Mounce Concise Greek Dictionary
ἀδελφή adelphē 26x
a sister; near kinswoman, or female relative, a female member of the Christian community
Abbott-Smith Greek Lexicon
ἀδελφή, -ῆς, ἡ
(< ἀδελφός), [in LXX for אָחוֹת;]
a sister: Mt 19:29, al.; metaph. (MM, VGT, s.v.), of a member of the Christian community: Ro 16:1, I Co 7:15 Ja 21:15, al.
Liddell-Scott-Jones — Greek-English Lexicon
ἀδελφή (adelphē) — sister. ἀδελφ-ή, ἡ, feminine of ἀδελφός, sister, Trag., E [Refs 4th c.BC+]: Ionic dialect ἀδελφ-εή, [Refs 5th c.BC+]; Epic dialect ἀδελφ-ειή, [Refs 4th c.AD+]; Doric dialect ἀδελφ-εά, [Refs 5th c.BC+], and in lyr, passages of Trag., [Refs 5th c.BC+]
2. kinswoman, [LXX]
3. term of endearment, [LXX]; applied to a wife, [Refs 3rd c.BC+]:—sister (as a fellow Christian), [NT]