One that flies or flees; usually written flier.

One that uses wings.

The fly of a jack.

In architecture, stairs that do not wind, but are made of an oblong square figure, and whose fore and back sides are parallel to each other, and so are their ends. The second of these flyers stands parallel behind the first, the third behind the second, and so are said to fly off from one another.

A performer in Mexico, who flies round an elevated post.