Definitions of sitter

1. a person who poses for a painter or sculptor

2. A bird that sits or incubates.

3. One who sits, specially to an artist; a bird that incubates.

4. One who sits; to sit down, to place one's self on a chair or seat; to settle; to fix one's abode; to be seated; to begin a siege; to sit for a portrait, to assume, for a limited time, a proper position to allow one's portrait to be painted by an artist; to sit out, to remain till all is done; to sit up, to rise from a recumbent position; not to go to bed.