What part of speech is threshold?

"Threshold" can be a few different parts of speech, depending on how it's used in a sentence:

* Noun: This is the most common usage, referring to the doorway itself or the point of entry into something.

* Example: "He crossed the threshold into the unknown."

* Adjective: This describes something that is at the point of entry or minimal for something to happen.

* Example: "He reached the threshold of pain."

* Verb: This is less common, but it means to reach a certain level or to cross a boundary.

* Example: "The patient's blood pressure thresholded at a dangerous level."

So, without more context, it's hard to say exactly what part of speech "threshold" is.