gliding

The word gliding is the continuous (-ing) form of glide, and it can also be used as a modifier, as in gliding motion. 

Saying that something is gliding often means that it’s moving smoothly and often quickly over a surface, such as how an ice hockey puck travels over the ice.

Similar words are sliding and coasting. The word skating is sometimes used in reference to how ice skates skate over ice.

Gliding is also commonly used to mean a particular kind of flying. For example, when a bird is gliding, it’s said to be soaring (flying without flapping its wings). When it’s an aircraft (such as a glider) or something else, you could say it’s sailing through the air.

Sometimes, saying that something is gliding in the air—like a ghost, for example—means not that it’s flying or soaring but rather that it’s floating or hovering (often right above a surface).

Gliding is also sometimes used a bit more figuratively, such as to describe how a dancer moves across a stage. In this case, the movement isn’t gliding in the literal sense, but rather a graceful, fluid motion. Such movement could also be described as floating or, more fancily, lilting.