From Longman Dictionary of Contemporary Englishsit in phrasal verbMEETto be present at a meeting but not take an active part in it on Would you like to sit in on some of my interviews? → sit→ See Verb table
Examples from the Corpus
sit on• In a unique demonstration they left their schools to sit in on a county council meeting discussing the cuts.Tim Hurst reports.• We sat in on a couple of French classes.• By the fall of 1992 I had already sat in on a number of black studies classes.• Both men sat in on all my meetings with the President.• During this same period, the trainee may also be asked to sit in on interviews in their bureau.• He also sat in on news meetings at a New York station to observe the protocol.• Have lunch in the canteen. Sit in on one of my lessons.• Ross sits in on the negotiations at will and feels free to raise proposals to bridge the two sides.• Invite the most junior person in your department to sit in on your executive meeting.sit-inˈsit-in noun [countable] PPROTESTa type of protest in which people refuse to leave the place where they work or study until their demands are considered or agreed tohold/stage a sit-in Several thousand students staged sit-ins and protest marches.Examples from the Corpus
sit-in• Demonstrators taking part in a sit-in in front of the law courts were beaten up by police.• Workers at the factory organized a sit-in to draw attention to their grievances.• In Pittsburgh, there were a few sit-ins, invasions of churches, minor civil disobedience.• Eventually they realized that they looked as if they had come to participate in sit-ins.• Hugh was at the Milton sit-in, where the workers won a fight to stop compulsory redundancies but lost the war.• I was there because of sit-ins and marches and riots.• There was the odd student sit-in and the National Union of Students was beginning to find a voice.• Southern police responded to sit-ins and civil rights marches with fire hoses, tear gas, beatings, and arrests.hold/stage a sit-in• We blocked off the main streets of the city centre and staged a sit-in at the Parque Libertad.• Students staged a sit-in to protest the firing of a popular professor.• It was unclear how far the students are willing to go, but some suggested staging a sit-in along police cordons.From Longman Business Dictionarysit-inˈsit-in noun [countable]HUMAN RESOURCES a type of protest in which people refuse to leave the place where they work or study until their demands are agreed toSeveral hundred employees of a national bank staged a sit-in to protest against plans to close branches and cut jobs. 