The word "or" is a conjunction. Conjunctions are words used to connect clauses, sentences, or words within a sentence. Specifically, "or" is a coordinating conjunction, which means it connects words, phrases, or clauses of equal importance. Coordinating conjunctions include "and," "but," "or," "nor," "for," "so," and "yet."

In the case of "or," it is used to present alternatives or choices. For example:

• "You can have tea or coffee." (Here, "or" presents a choice between tea and coffee.)
• "Would you like to go to the park, or would you prefer to stay home?" (In this sentence, "or" connects two clauses, presenting two options.)

"Or" can also be used in negative constructions to indicate that neither of the options is true or applicable:

• "I don't like apples or oranges." (This means the speaker dislikes both apples and oranges.)

In addition to its role as a coordinating conjunction, "or" can sometimes function as part of correlative conjunctions, which are pairs of conjunctions that work together to connect ideas. For example:

• "Either you come with us, or you stay here." (Here, "either...or" is a correlative conjunction pair that presents two mutually exclusive options.)

In summary, "or" is a versatile word that primarily functions as a coordinating conjunction, helping to connect and present alternatives in sentences. Its role is essential in creating clear, logical, and grammatically correct expressions in English.