Jiggle means to move with small, quick, shaky movements, or to make something move that way. When you jiggle a doorknob to see if it's locked, you're wiggling it rapidly back and forth. A bowl of gelatin jiggles when you tap the table because it's soft and wobbly.

The word captures that particular wiggly, bouncy quality of movement. You might jiggle your loose tooth with your tongue, or jiggle a vending machine when your snack gets stuck. Sometimes people jiggle their leg nervously while sitting, making their knee bounce up and down rapidly.

The movement is usually small and repeated, not one big shake. Picture the difference between giving something one hard shake versus lots of tiny, quick ones. That repeated, wobbly motion is what makes something jiggle. A car driving over a bumpy road might make everything inside jiggle and rattle.

As a noun, a jiggle is one of those small, shaky movements: the jiggle of a loose tooth, or the jiggle of a bowl of gelatin.