1 [u] when something becomes smaller or shorter:
Cold causes contraction of the metal.
The contraction of this muscle raises the lower arm.
2 [C] one of the very strong and usually painful movements of the muscles in the womb that help to push the baby out of the mother's body during the process of birth:
She was having
regular strong contractions every four minutes.
3 [C] 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'.