Lexical Definition

‎χάσμα‎ chásma (khas'-mah) chasm ^G:N-N
from a form of an obsolete primary (to "gape" or "yawn")

gulf.

• a "chasm" or vacancy (impassable interval)

Abbott-Smith

χάσμα, -τος, τό (< χάσκω, to yawn), [in LXX: II Ki 18:17 (פַּחַת)* ;]
a chasm, wide space: Lk 16:26.†

Abbott-Smith References

Liddell-Scott-Jones

χάσμα, ατος, τό,

(χαίνω) yawning chasm, gulf, χ. μέγα, of Tartarus, [Refs 8th c.BC+]; χθονός, πέτρας, [χάσματα 5th-6th c.AD: Julianus Laodicensis Astrologus in “Catalogus Codicum Astrologorum” 1.134. ">Refs 5th c.BC+]

__II open, gaping mouth, χ. θηρός [Refs 5th c.BC+]; as forming a helmet, [Refs]; of a yawning gulf, χάρυβδις.. ἄρμα περιβαλοῦσα χάσματι [χάσμασιν “Anthologia Graeca” 11.379 (6th c.AD: Agathias Historicus et Epigrammaticus)">Refs 6th c.AD+]; χ. φάρυγος, of a lion,[Refs 7th c.BC+]
__III generally, any wide opening, θυρέτρων χ. ἀχανές [Refs 4th c.BC+]; also, expanse, of the sky and sea, χ. πελάγεος τὸ δὴ Αἰγαῖον καλέεται [Refs 5th c.BC+]