Correct spelling, explanation: both while and whilst are correct, but their usage can vary based on regional preferences. In American English, while is more commonly used, while in British English, both while and whilst are used. Generally, whilst is considered a bit more formal and is less common in everyday conversation. So, if you’re writing for an American audience or in a more informal context, it’s advisable to use while. If you’re writing in a formal or British context, you can choose either, but whilst may be preferred in more formal writing. It’s worth noticing that while can also be used as a noun and a verb, and whilst can’t.

Definition of while:
1. Conjunction, during the time that; at the same time as
I was reading a book while my friend was watching a movie.
While the sun was shining brightly, dark clouds began to gather on the horizon.
2. Noun, a period of time
I’ll be away for a while, so please take care of my plants in the meantime.
During the while she spent waiting for her appointment, she caught up on some reading.

Collocations with while:
Some most commonly used collocations include:
1. For a while: this refers to a period of time.
I haven’t seen her for a while.
2. A little while: this also refers to a short period of time.
Wait here for a little while; I’ll be back.
3. In a while: this is used to indicate that something will happen after some time.
I’ll call you in a while.
4. After a while: this indicates an action that happens following a period of time.
After a while, he finally understood the instructions.

Correct spelling, explanation: whilst and while are both conjunctions that can be used to indicate a contrast or a simultaneous occurrence of two actions. Whilst is generally considered more formal than while – in more formal or written contexts, this word might be preferred. In everyday conversation and informal writing, while is more commonly used. Moreover, whilst is more commonly used in British English, and while is used in both British and American English. In American English, whilst is less common, and while is the more standard choice.