There are several types of feathers on the wing, each with their own function. Primary feathers are essential to flight, and are the biggest and the largest ones. They are extremely light, but incredibly stiff. Their shafts (the hard stem that supports the feather) are made up of a material very similar to that which makes up your fingernails - hard, durable, and tough. There are ordinarily ten primary feathers.

The large outermost feathers of the wing. They form part of the flight feathers.

The outermost nine or ten feathers of a bird's wings. Primaries are the major flight feathers.

nine or ten long flight feathers attached to the “hand” of a birdâ€(tm)s wing

The first ten feathers on the wing starting at the tip working towards the middle. Out of sight when the bird is resting.