A precis is a summary of something's main points. If you've ever jotted down notes about your main ideas before writing a persuasive essay, you've used a precis.
Precis looks like precise, and of course, you always want your precis to be precise. But the words are pronounced differently. Precis comes from the French word précis, so say it like this: "PRAY see." Or you can accent the other syllable: "pray SEE." The s is only pronounced if the word is plural: "PRAY sees." The spelling stays the same.