1: ἔσω
(Strong's #2080 — Adverb — eso — es'-o )

an adverb connected with eis, "into," is translated "inner" in the AV of Ephesians 3:16 (RV, "inward"); after verbs of motion, it denotes "into," Mark 15:16; after verbs of rest, "within." See WITHIN.

2: ἐσώτερος
(Strong's #2082 — Adjective — esoteros — es-o'-ter-os )

the comparative degree of No. 1, denotes "inner," Acts 16:24 (of a prison); Hebrews 6:19 , with the article, and practically as a noun, "that which is within (the veil)," lit., "the inner (of the veil)." Cp. Eng., esoteric.

CHAMBER