Noun, pl. contractions
2. The process of becoming smaller. (Google Dictionary)
3. The process in which a muscle becomes or is made shorter and tighter. (Google Dictionary)
4. A strong and often painful shortening of the uterine muscles prior to or during childbirth. (wiktionary.org)
5. A distinct stage of wound healing, wherein the wound edges are gradually pulled together. (wiktionary.org)
Word origin: From Latin contractiō.