* Adjective: Describing a noun (e.g., "He wore short pants.")
* Adverb: Modifying a verb, adjective, or another adverb (e.g., "He stopped short of the finish line.")
* Noun: Referring to the concept of shortness itself (e.g., "The short of it is, we're out of time.")
To figure out the part of speech, you need to look at how the word is used in the sentence.