CONTRACTION

[noun] [U]Cold causes the contraction of the metal.The contraction of this muscle causes the lower arm to be raised.In the process of giving birth a contraction is one of the very strong and usually painful movements of the muscles in the womb that help to push the baby out.A contraction is also a shortened form of a word or combination of words which is often used instead of the full form in spoken English.'Won't' is a contraction of 'will not'.