稚海藻[wakame] wakame (species of edible brown seaweed, Undaria pinnatifida)
稚子[mizugo] aborted, stillborn or miscarried foetus (fetus)
稚気[chiki] childishness
稚魚[chigyo] fry (young fish)
稚児[chigo] (festivity) page

稚拙[chisetsu] unskillful
稚鰤[warasa] middle-sized Japanese amberjack (species of yellowtail, Seriola quinqueradiata)
丁稚[decchi] apprentice
丁稚奉公[decchiboukou] apprenticeship
稚い[itokenai] very young

乳幼児[nyuuyouji] infants
幼い[osanai] very young
幼馴染[osananajimi] childhood friend
幼魚[yougyo] fry (young fish)
幼形進化[youkeishinka] paedomorphosis

幼子[osanago] infant
幼児[youji] infant
幼児ポルノ[youjiporuno] child pornography
幼児語[youjigo] baby talk (like choo-choo for train, etc.)
幼時[youji] childhood

孺子[jushi] child

絛虫[jouchuu] cestode

絛虫類[jouchuurui] cestodes

蛹化[youka] pupation
蛹虫[youchuu] pupa

茶色蛹貝[chairosanagigai] widespread column (species of land snail, Pupilla muscorum)