Correct spelling, explanation: both theatre and theater are correct and can be used interchangeably. The first version is more popular in British English and the other one – in American English. They share the same etymological origin. Both words can be traced back to the Greek word theatron, which referred to a place for viewing or contemplating. Theatron is derived from the verb theaomai, meaning to see or to watch. So, while the spellings may differ, the words have a common origin in ancient Greek and have maintained a consistent meaning related to a place for viewing or presenting performances.

Definition of theatre:
Noun, a building or outdoor area in which plays and other dramatic performances are given.
We eagerly awaited the curtain to rise in the grand theatre, anticipating a night of captivating performances.
The local theatre, with its ornate architecture and rich history, is a cultural gem that showcases a diverse array of artistic productions.

Collocations with theatre:
Some of the most commonly used collocations include:
1. Regional theatre: refers to theatres outside major urban centers that focus on producing a variety of plays and performances.
Many aspiring actors start their careers in regional theatre before making the leap to larger, more prominent stages.
2. Black box theatre: a simple, flexible performance space, often with black walls and a flat floor, allowing for various staging configurations.
The intimate atmosphere of a black box theatre provides a unique experience for both performers and the audience.
3. Outdoor theatre: a theatre that presents performances in an outdoor setting, often during the warmer months.
The city hosts outdoor theatre events in the park, allowing people to enjoy performances under the open sky.
4. Children’s theatre: productions specifically designed for a young audience, often adapted from children’s literature or original works for children.
Children’s theatre is a great way to introduce young minds to the world of storytelling and creativity.

Correct spelling, explanation: remember that both theater and theatre are correct versions of the same word. The first one is more commonly used in American English, while the other one is associated with British English. The differences in spelling between British English and American English often arise from historical developments and linguistic preferences. The variation in the spelling of words like theater and theatre can be traced back to the influence of certain individuals, spelling reforms, and the evolving nature of the English language.