playpen (space for children to play)

establishment, foundation, setting up (a business etc.) / installation (of equipment)

set up, establish, found / install, put in, erect

baby, infant / baby (term of endearment)

child

circle (geometric shape) / circle (group of people with a common goal or interest) / circle (group that produces dōjin works)

safety; security

safe; secure

(chiefly women's speech) first person singular pronoun: I, me

person who ruins a group dynamic