What part of speech is cataract?

"Cataract" can be two parts of speech depending on how it's used:

* Noun: When referring to the eye condition, it's a noun. For example: "The doctor diagnosed him with a cataract."

* Adjective: When describing something as resembling a waterfall, it's an adjective. For example: "The cataract roared down the mountainside."

It's important to look at the context of the sentence to determine the part of speech.