perfect and without blemish; flawless

(number theory) perfect number, a positive integer that is equal to the sum of its positive divisors, excluding the number itself

(mathematics) panmagic square

aquaculture that spans an entire lifespan in complete captivity

(offensive, Internet slang) Alternative form of 子供部屋おじさん

(offensive, Internet slang) a man whose age is greater than about thirty or forty who lives in one's child room and with one's parent(s).

single room

double room

perfectionist

(music) perfect fifth (interval between the first and second overtones or of seven semitones)