Dictionary entry

ὕαλος

G. Abbott-Smith's A Manual Greek Lexicon of the New Testament

ὕαλος, -ου, ὁ

[in LXX: Jb 28:17 (זְכוּכִית) *;]

1. (Hdt.) a clear transparent stone.

2. (from Plat. on) glass: Re 21:18, 21.†