Meaning

noun the region that is inside of something

noun the inner or enclosed surface of something

adjective relating to or being on the side closer to the center or within a defined space

originEtymology tree Middle English ynneside English inside From Middle English ynneside; equivalent to in- + side. Compare German Innenseite (“inside”), Danish inderside (“inside”), Swedish insida (“inside”), Dutch binnenzijde (“inside”), German Low German Binnensied, Binnersied (“inside”), Saterland Frisian Binnersiede (“inside”).

Etymology from Wiktionary, CC BY-SA 3.0