Every writer’s nightmare: Everyone vs. every one

These two words drive everyone nuts! Or is it “every one nuts”?

Everyone (one word, no space) is a pronoun meaning “every person in a group,” as in “Everyone at school was a real jerk today!” my teen daughter exclaimed, as she swung open the door.

Every one (two words, a space) means “each” and so refers to single, standalone objects that usually are part of a larger set, as in Every one of those apples has a worm in it!

One trick to get the right spelling is to simply use each in place of every. If the sentence makes sense (Each one of those apples has a worm in it!), use every one. If the sentence doesn’t make sense (Each one at school was a real jerk today!), then use everyone.