By Megan, Courtney, Jarrett, and Lexie
Word choice is the use of language that communicates in a functional way.
Basically it is the different words you use.
The dog ran. Ran could be replaced with the word frolicked.
The dog frolicked.
Pros and cons
Overall, using bigger, more descriptive words is better and contributes to the sentence. But it can be overdone. For example, it will be hard to read a story with a sentence like this.
The magnanimous, magniloquent pachyderm observed the malapropisms.