What part of speech is the word heard?

The word "heard" can be two different parts of speech, depending on its use in a sentence:

* Past participle of the verb "hear": In this case, it acts as a verb and describes a past action. Example: "I heard a knock at the door."

* Past participle used as an adjective: Here, it describes a noun and functions as an adjective. Example: "The heard news was shocking."

To determine the part of speech, you need to look at how the word is used in the specific sentence.