Lexical Definition

‎ζόφος‎ zóphos (dzof'-os) darkness ^G:N-M
akin to the base of ‎νέφος‎

blackness, darkness, mist.

• gloom (as shrouding like a cloud)

Abbott-Smith

** ζόφος, -ου, ὁ (akin to γνόφος, q.v.), [in Sm.: Ex 10:22, Jb 28:3, Ps 10(11):2* 90(91):6*, Is 59:9*;]
in Hom. the gloom of the under-world; hence, darkness, deep gloom (poët. and late prose writers): He 12:18, II Pe 2:4, 17, Ju 6, 13.†

Abbott-Smith References

Liddell-Scott-Jones

ζόφος, ὁ,

nether darkness, ἱεμένων Ἔρεβόσδε ὑπὸ ζόφον [NT+8th c.BC+]; Ἀΐδης δ᾽ ἔλαχε ζόφον ἠερόεντα obtained the realms of gloom for his share, [Refs 8th c.BC+]

__2 generally, gloom, darkness, [NT+8th c.BC+]; χειμέριος ζ. the gloom of winter, [Refs 5th c.BC+]
__II the dark quarter, i.e. the West, ἤδη γὰρ φάος οἴχεθ᾽ ὑπὸ ζόφον [Refs 8th c.BC+]; ποτὶ ζόφον, opposed to πρὸς ἠῶ τ᾽ ἠέλιόν τε, [Refs 8th c.BC+] (the North accusative to [Refs 1st c.BC+]; Γαδείρων τὸ πρὸς ζόφον to the west of.., [Refs 5th c.BC+] —poetical and later Prose. (Prob. _cognate_ with ζέφυρος.)

_{LSJ Scripture Refs: Heb.12.18}