Sitter, Willem de Sitter - Dutch astronomer who calculated the size of the universe and suggested that it is expanding (1872-1934)
sitter - an organism (person or animal) that sits
artist's model, sitter - a person who poses for a painter or sculptor
baby-sitter, babysitter, sitter - a person engaged to care for children when the parents are not home
brood hen, broody, broody hen, setting hen, sitter - a domestic hen ready to brood