Correct spelling, explanation: the words while and whilst have a common origin and share similar etymological roots. Both words trace their ancestry back to Old English. In Middle English, while and whilst were used interchangeably, but over time, whilst persisted as a more formal or literary form. While the etymological roots are the same, the preference for one form over the other in modern English has to do with historical usage, linguistic evolution, and regional variations. While is more commonly used in both British and American English, with whilst being somewhat more prevalent in formal or British English contexts.

Definition of whilst:
1. Conjunction, during the time that; at the same time as
She decided to cook dinner whilst her husband took care of the children’s homework.
He enjoyed reading a book whilst sipping his favorite tea in the cozy armchair.
2. Adverb, during which; while
The children played in the garden whilst their parents prepared a picnic.
She listened attentively to the lecture whilst taking thorough notes.

Collocations with whilst:
Some most commonly used collocations include:
1. Whilst reading: this collocation indicates an action happening during the act of reading.
She discovered the news whilst reading the morning paper.
2. Whilst studying: this collocation suggests an action occurring during the process of studying.
He made some interesting observations whilst studying the behavior of birds.
3. Whilst working: this collocation indicates an action taking place during the act of working.
She had a moment of inspiration whilst working on her project.
4. Whilst traveling: this collocation suggests an action happening during the period of travel.
He learned a new language whilst traveling abroad.

Correct spelling, explanation: while and whilst are often used interchangeably, and in many contexts, they convey the same meaning. Both words can function as conjunctions to indicate a contrast or a simultaneous occurrence of two actions. While functions as a noun, verb, conjunction, or preposition in a sentence and whilst only functions as a conjunction or preposition. In American English, while is the standard and more commonly used conjunction. Whilst is less common in American English, and its use might sound somewhat formal or archaic. In British English, the choice between while and whilst may be influenced by personal preference, formality, or stylistic considerations.