Correct spelling, explanation: the difference between theater and theatre is primarily a matter of regional spelling variations. Both spellings are correct, but the usage depends on the English variant. In general, if you are writing in American English, you should use theater, and if you are writing in British English, you should use theatre. However, it’s worth noting that these distinctions are not always strictly adhered to, and you may find some variation in usage even within a particular region. Additionally, in modern times, theater has become widely accepted and used in British English as well, especially in informal contexts.

Definition of theater:
1. Noun, a cinema
We decided to spend our Friday night at the local theater, catching the latest blockbuster film.
The new theater in town boasts state-of-the-art technology, providing an immersive cinematic experience for moviegoers.
2. Noun, a building, room, or outside structure with rows of seats, each row usually higher than the one in front, from which people can watch a performance, a movie, or another activity
The historic theater in the downtown district has been hosting Broadway productions and concerts for over a century.
We bought tickets to the play at the newly renovated theater, eager to experience the magic of live performances in such a beautiful venue.

Collocations with theater:
Some of the most commonly used collocations include:
1. Live theater: refers to performances that are presented to a live audience, such as plays, musicals, or dance shows.
She has a deep passion for live theater and attends every play that comes to town.
2. Movie theater: a venue where films are shown on a large screen for public viewing.
Let’s meet at the movie theater at 7:00 PM to catch the latest release.
3. Community theater: a theater that is run by and for the local community, often involving amateur actors and volunteers.
The community theater is putting on a production of Shakespeare’s “A Midsummer Night’s Dream” next month.
4. Theater production: refers to the entire process of putting on a play or performance, from casting to rehearsals to the actual show.
The theater production of “Les Misérables” required months of intense rehearsals to perfect the elaborate musical numbers.

Correct spelling, explanation: theatre is a correct word. The choice between theater and theatre depends on your preference and the style guide you are following. Both spellings are correct, but their usage is associated with different regional variations of English. If you are writing for an American audience or following American English conventions, use theater. If you are writing for a British audience or following British English conventions, use theatre. In some cases, the choice may also depend on the context or personal preference, as both spellings are generally understood in both American and British English.