Is the word to a preposition conjunction or interjection?

The word "to" can be a preposition or an infinitive marker. It is not a conjunction or an interjection.

Here's how to tell:

* Preposition: "To" indicates a relationship between a noun or pronoun and another word in the sentence.

* Example: "I went to the store." (Here, "to" shows the direction of movement.)

* Infinitive Marker: "To" is used before a verb to form an infinitive.

* Example: "I want to eat." (Here, "to" marks "eat" as the infinitive.)

Conjunctions connect words, phrases, or clauses.

* Example: "I went to the store, and I bought milk." ("and" connects two clauses)

Interjections express strong emotions or sudden feelings.

* Example: "Wow! That's amazing!" ("Wow" expresses surprise)