Quick Definition
θρῆνος, ου, ὁ n.m. wailing, lamentation
Strong's Definition
wailing
Derivation: from the base of G2360 (θροέω);
KJV Usage: lamentation
Thayer's Greek Lexicon
θρῆνος, -ov, 6, (θρέομαι to cry aloud, to lament; cf. Germ. Thréne [(?), rather drénen; Curtius ὃ 317]), α lamentation: Mt. ii. 18 Ree. (Sept. for ADP, also ‘2; O. T. Apocr.; Hom., Pind., Tragg., Xen. Ages. 10, 3; Plat., al.)
Mounce Concise Greek Dictionary
Abbott-Smith Greek Lexicon
θρῆνος, -ου, ὁ,
[in LXX chiefly for קִינָה;]
a lamentation: Mt 2:18, Rec.†
Moulton & Milligan — Vocabulary of the Greek NT
κλαυθμός. The reduction of ἂν to a, which can be freely illustrated from the less educated papyri after i/B.c. (cf. Mayser Gr. p- 114}, is seen in the form κλαθμός, read six times in the Washington Manuscript according to Sanders (p. 21 n.: see Moulton Gy. ii. p. 87). The MGr κλάματα (pl.) shows the same phonetic change from the classical form κλαύματα. MGr also κλάψα (cf. the MGr aor. ἔκλαψα).
Liddell-Scott-Jones — Greek-English Lexicon
θρῆνος (thrēnos) — lamentation. θρῆνος, ὁ, (θρέομαι) dirge, lament, [Refs 8th c.BC+]; θ. οὑμός for me, [Refs 4th c.BC+]
2. complaint, sad strain, [Refs]; Τοργόνων οὔλιον θ. [Refs 5th c.BC+]: plural, lamentations, θρήνων ᾠδάς [Refs 5th c.BC+]; title of poems by Pindar, [Refs 1st c.BC+]