Lexical Definition

‎μέγεθος‎ mégethos (meg'-eth-os) greatness ^G:N-N
from ‎μέγας‎

greatness.

• magnitude (figuratively)

Abbott-Smith

μέγεθος, -ους, τό (< μέγας), [in LXX chiefly for קוֹמָה;]
greatness: Eph 1:19 (cf. MM, xvi, s.v. μέγας).†

Abbott-Smith References

Liddell-Scott-Jones

μέγεθος,

Ionic dialect (not [Refs 5th c.BC+] μέγᾰθος [Refs 5th c.BC+], εος, τό: (μέγας):— greatness, magnitude, opposed to πλῆθος, [Refs 5th c.BC+]

__I in [Refs 8th c.BC+] always stature, of men and women, εἶδος ἀκιδνοτέρη μέγεθός τ᾽ εἰσάντα ἰδέσθαι [Refs 8th c.BC+]: then, generally, size, μύρμηκες μεγάθεα ἔχοντες κυνῶν ἐλάσσονα [Refs 5th c.BC+]; of sound, loudness, βοῆς μ. [Refs 5th c.BC+] adverb, λίθου λάμποντος μέγαθος, ={μεγάλως}, [Refs 5th c.BC+]; but usually, in size, τεῖχος κατὰ τὸν Ἀθηνέων κύκλον.. τὸ μ. [Refs 5th c.BC+]: also in plural, ποταμοὶ οὐ κατὰ τὸν Νεῖλον ἐόντες μεγάθεα [Refs 5th c.BC+]
__I.2 frequently in dative, μεγέθει.. ἐκπρεπεστάτη in stature, [Refs 5th c.BC+]; κρητῆρες μεγάθεϊ μεγάλοι[Refs]; σμικρός[Refs 4th c.BC+]
__II of quality and degree, greatness, magnitude, πόνων [Refs 5th c.BC+]; importance, μ. ἐχούσας πράξεις [Refs 1st c.BC+]
__II.2 might, power, [Refs 5th c.BC+]
__II.3 greatness, magnanimity, [Refs 1st c.AD+]
__II.4 Rhet., loftiness, sublimity, μ. περιτιθέναι τοῖς πράγμασιν [Refs 4th c.BC+]: in plural, sublime objects, [Refs]
__III in Mathematics texts, magnitude, [Refs 5th c.BC+]; extension, [Refs 3rd c.AD+]: in plural, magnitudes, [Refs 5th c.BC+]
__III.2 Astron., magnitude, of stars, [Refs 1st c.BC+]
__IV Grammars, metrical length, τὸ μέγιστον μ. τρίχρονον [Refs 2nd c.AD+]
__IV.2 τὰ ἐν τῷ μέτρῳ μ. the recognized lengths of lines in a metre, [Refs 7th c.AD+]
__V τὸ μ. τινός, as title, his Highness, [Refs 3rd c.AD+]; τὸ σὸν μ. [Refs]