Douglas Harper's Etymology Dictionary
Wiktionary
n. A piece of cloth used to cover the head.
Wikipedia
A do-rag (also spelled variously as a doo-rag, dew-rag, du-rag or durag), is a piece of cloth used to cover the top of one's head, sometimes made of nylon material and having a "skullcap" fit. It may also be referred to as a " wavecap". According to the Oxford English Dictionary and Merriam-Webster dictionary, the term derives from 'do as in hairdo.
Usage examples of "do-rag".
Maurice said it was too cold to be outside, the dude in his lilac do-rag and tailored black pea jacket, enough shoulders in the coat for White Boy Bob-White Boy wearing a wool shirt hanging out over his T-shirt-coming behind them up the ramp to the front door of the Kronk Recreation Center at McGraw and Junction, a two-story red-brick building that looked to Glenn like a public library no one used in a poor section of town.
I got some shades in my pack and a bandana I can like tie like a do-rag?