複 is built from the 礻 (altar / spirit (left)) and 复 (return (top of 復)) components.
It belongs to a phonetic family with 復, 腹, and 覆 — they share the 复 component and the reading フク.
A common word using 複 is 複雑 (ふくざつ), meaning “complexity, complication”.
Don't confuse it with 復, 腹, and 覆 — 彳 return, 衤 duplicate, 月 belly, 覀 cover
