A robinhood is when you shoot an arrow and it hits exactly inside another arrow, which when you look at it, it looks like one long arrow.

A fletch is the feathers on the arrow which help stabilizes an arrow in flight, usually have 3 feathers, and some arrows you will see 4 fletches.

Nocks are the small plastic pieces that are forked shaped either inserted over the arrow or inside the arrow behind the fletches, the nock helps hold an arrow in place on the bowstring.

Welcome to archery/bowhunting !!!!!!!