Contraction

収縮

shūshuku

((sometimes reversible) contracting or reduction in length, scope, size, or volume)

攣縮

renshuku

(shortening of a muscle during its use)

短縮形

tanshuku-kei

(shortened form of a word, often with omitted letters replaced by an apostrophe or a diacritical mark)

約音化

yakuon-ka

(process whereby one or more sounds of a free morpheme are reduced or lost)

陣痛

jintsū

(strong and often painful shortening of the uterine muscles prior to or during childbirth)