Lose sounds like snooze. If you lose something, you don’t have it anymore. Add an "o," and loose rhymes with goose and describes something that’s not attached.
The word lose has been through some changes since it hit the scene in the year 900. Now you can lose a game, lose your mind, lose control, lose your temper, lose your… train of thought, but you can also lose your car keys or ten pounds. Here are some current examples (because Old English would be confusing):
"If you know you eat all the time because you need something, but you aren’t sure what you need, diets won’t help you lose weight.” (US News)
"Sometimes I have trouble staying focused and I lose my train of thought,” Ford said. (Washington Times)
Loose is also an old word. Its meaning overlapped with lose's at some point, but now they’re separate. Loose got loose! It means not attached well, like a loose tooth, or free like a loose dog that’s off the leash. Lips come in pairs, like the "o’s" in loose, and loose lips sink ships. Here are more examples:
“State police say they're not sure how many chickens are on the loose." (US News)
"And sheepskin coats flowed loose and luxuriously around the body." (Washington Post.)
If you get them mixed up, don’t feel bad: lose and loose do have a shared history. To remember the difference, think of how a goose can get loose. But when loose loses an “o,” it’s gone forever. If you snooze, you lose.