Similar to the dolphin, a purpose is an ocean-dwelling cetacean that…
Oh, okay. We’ll go ahead and stop ourselves right there.
Readers of academic essays don’t want to feel like they’re wasting their time when they read an essay, so the purpose of an essay is to convey information that’s important or unique in some way. This unique idea is usually concisely expressed in a thesis statement or a focusing statement. Although sometimes it is also expressed in a drawn-out, rambling way. Guess which version your teacher would prefer.
Readers will want to understand the purpose of every little thing that shows up in an essay—they’re funny that way. Everything should be working together to illustrate, prove, or explain a point. This doesn’t mean anecdotes or asides are totally off limits, but the reader must understand why they’re in the essay and worth the reader’s time. Unless the anecdote or aside is uproariously funny, in which case all bets are off. Ish.