to (cause someone to) be in a position in which the lower part of the body is resting on a seat or other type of support, with the upper part of the body vertical: to sit at a table/desk. to sit in an armchair. to sit on a chair/a horse/the ground. He came and sat (down) next to me.

verb (used without object),sat or (Archaic) sate [sat, seyt]; sat or (Archaic) sitten [sit-n]; sitting. to rest with the body supported by the buttocks or thighs; be seated.