1. Subordinating conjunction: This is the most common usage. It introduces a dependent clause that describes the time or duration of the action in the main clause.
Example: *While* I was eating, the phone rang.
2. Coordinating conjunction: In this case, "while" acts like "but" or "although" to show a contrast between two clauses.
Example: I love to go to the beach, *while* my sister prefers the mountains.
Note: It's important to understand the context to determine which type of conjunction "while" is functioning as.