A synopsis is a short account of the main events or main ideas of something longer — a book, a film, a play, a piece of research. It tells you what happens, in order, briefly. You meet it on the back of a novel, in a programme at the theatre so you know the story before the opera starts in Italian, and in the film and publishing industries, where a writer must send a one-page synopsis before anyone will read the whole script. Note the difference from a review: a synopsis reports, it does not judge, and unlike a trailer it usually does tell you the ending, because its job is to inform someone who needs to know, not to tempt a customer. It is a fairly formal word — in ordinary speech people say 'summary' or 'a quick rundown'. The plural is irregular: two 'synopses' (sin-OP-seez). The verb 'synopsise' exists but is rare; people say 'summarise'.