1N-COUNT (分娩时的)子宫收缩,宫缩 When a woman who is about to give birth has contractions, she experiences a very strong, painful tightening of the muscles of her womb. (分娩时的)子宫收缩,宫缩
2N-COUNT (词的)缩约形式 A contraction is a shortened form of a word or words. (词的)缩约形式
'It's' (with an apostrophe) should be used only as a contraction for 'it is'. [+ for]