Strong's Exhaustive Concordance: Probably from limen (through the idea of nearness of shore); a pond (large or small) -- lake. https://biblehub.com/greek/3041.htm
biblicaltheology.org
"'The lake of fire'" appears as a place of punishment, of perpetual torment, not of annihilation (20:10). The beast (19:20); the pseudo-prophet (19:20; 20:10); the devil (20:10); the wicked of varying description (20:15; 21:8), are cast into it. When the same is affirmed of death and Hades (20:14), it is doubtful whether this is meant as a mere figure for the cessation of these two evils personified, or has a more realistic background in the existence of two demon-powers so named (compare Isaiah 25:8; 1 Corinthians 15:26,54; 2 Esdras 7:31)" (The International Standard Bible Encyclopedia, Vol. III:1822)
