Click here for more examples:

Foul Tip

A foul tip is a special category of foul ball that is treated the same way as a swing and a miss, even though it is, indeed, a foul ball. Specifically, a foul tip is a foul ball that the bat only barely touches, such that the path of the ball isn’t really affected. If you’re watching a game in person, you might not be able to tell the ball was tipped at all, unless you’ve got really good seats¹, or unless you notice the umpire making the "foul tip" sign by by holding one arm up at an angle with the palm facing down, and sliding the other hand off the top.

The key to a foul tip is that the ball goes directly into the catcher’s glove, like the batter never even swung at it to begin with. As long as the ball is caught cleanly (by which we mean without hitting the dirt, or anything else), then the ruling is a foul tip strike. A foul tip strike is a strike no matter what the count was beforehand. This is unlike a standard foul ball; if you hit such a foul with two strikes in the count, the count stays the same as it was before the pitch. If you foul tip a pitch with two strikes, it’s strike three.