Pronunciation: (sit'ur),[key] —n. 1. a person who sits.
2. a brooding hen.
3. a person who stays with young children while the parents go out; baby-sitter.
4. a person who provides routine or custodial care temporarily or part-time, as for an elderly person or a pet whose owner is on vacation.
5. Slang.the buttocks; rump.
Pronunciation: (sit'ur),[key] —n. Wil•lem de Pronunciation: (wil'um du),[key] 1872–1934, Dutch astronomer and mathematician.