Hey, wasn’t that one of our school band’s songs?

The bold word is "Hey."

conjunction
interjection
preposition
adjective

Don't guess.

Interjection.

To determine the part of speech of the word "Hey," you can follow these steps:

Step 1: Identify the word in question.
In this case, the word in question is "Hey."

Step 2: Understand the different parts of speech.
There are several parts of speech in the English language, including nouns, pronouns, verbs, adverbs, adjectives, prepositions, conjunctions, interjections, and articles.

Step 3: Analyze the word "Hey" in context.
In the given sentence, "Hey" is used to get someone's attention or to express surprise or greeting. It is not functioning as a noun, pronoun, verb, adverb, adjective, or article.

Step 4: Determine the correct part of speech.
The word "Hey" in this context is an interjection. Interjections are words or phrases used to express strong emotions or sudden feelings.

Therefore, the answer is "interjection."

The bold word "Hey" is an interjection. It is commonly used to get someone's attention or express surprise, joy, or other strong emotions.