sit in

See also: sitin and sit-in

English

sit in (third-person singular simple present sits in, present participle sitting in, simple past and past participle sat in)

(idiomatic) To attend a class, educational presentation, meeting, etc. for one time, as a visitor.
(music) To take part in a group musical performance, especially a jazz session, as a temporary guest.
To participate in a sit-in protest.
- 1987 April 4, Kim Westheimer, “Homeless Women & Children Sit-In”, in Gay Community News, page 4:
  Over 200 homeless women and children sat-in over night at the state house to protest inadequate state funding for Aid to Families with Dependent Children (AFDC).

to attend for one time