居 is built from the 尸 (corpse / body) and 古 components.
It reads コ like 古, as do 個, 故, 固, and 湖 — learn 古 once and the family's reading comes with it.
A common word using 居 is 居る (いる), meaning “(humble) to be (animate), to exist”.
Kanji that look similar include 刷, 屈, 届, and 泥.
