Whether you use the spelling theatre or theater will depend on where you hail from. In American English, the spelling is theater; in Britain and the rest of the English-speaking world, theatre is used. The spelling you choose—theater vs. theatre—should align with your audience’s preference.
Why Are There Different Spellings: “Theatre” vs. “Theater”?
Theater has roots in both Greek and Latin and came to English through the Old French word theatre. Theatre and similar words ending in -re were sometimes spelled with the -er until the 1660s, when the French-borrowed -re spellings came to be preferred; before that, both spellings were considered equally correct. Chaucer, for example, spelled it theatre. Shakespeare, on the other hand, spelled it theater. Today, theatre is considered the correct spelling in Britain and in most English-speaking countries other than the United States.
In the eighteenth century, following the American Revolutionary War, sought to create a standard literacy curriculum specifically for his fledgling nation. Not only did he succeed at replacing British textbooks with new American versions, but he also published his own meticulously researched dictionary, notable for its reformed spellings. The separation of British and American spellings, and in some ways, punctuation, had begun.
Webster was the man who took the u out of colour and turned musick into music. He preferred spellings that were simpler and closely modeled pronunciation, which was why theatre became theater and similar words, like centre, became center. Most of the newly respelled -er words caught on in the United States, especially in the last century or so.
When to Use “Theatre”
Choose the spelling theatre whenever your audience will likely be predominantly using British English or its local variant. Canada, Australia, New Zealand, India, and South Africa, for example, all use the spelling theatre. American English and British English do have remarkable differences, don’t they?
There are notable exceptions, however. Take the New York theater scene. We refer to the Broadway Theater District, yet many of the most frequented Broadway theaters actually have theatre spelled out on their marquees:
And of course, there is Ford’s Theatre in Washington, D.C., which is famous for being the site of Abraham Lincoln’s assassination.
Across the pond, things are much simpler.
When to Use “Theater”
If your audience speaks American English, use theater. Theater is also the most predominant spelling on the internet, statistically speaking, if that is your determining factor.
Manuel is interested in trying his luck in the musical theater scene.
Cinema or Movie Theater?
Brits and Americans don’t just spell differently; some of the vernacular is different as well. Brits talk about going to the cinema or catching a film. An older British expression for going to see a film is going to the pictures. Americans speak of the movies as a slang abbreviation for motion pictures. While in British English, a building called a theatre is for only plays and musicals, American English also has movie theaters. Canadians have a blended approach to the place where they view blockbusters: they call them (and spell them) movie theatres.
We plan to catch a film with our neighbors on Saturday. (British English)
I remember the days when we went to the pictures every Friday evening. (British English)
Please don’t make me go to the movie theater on Main Street. They put too much butter on their popcorn. (American English)
She refused to go to the movies with my cousin Albert. (American English)
Whether you spell it theater or theatre, or you refer to films, movies, or the cinema, it is unlikely that your readers will be confused by whichever word you choose.