What's the difference between a hijab, chador, niqab and burka?

Muslim women in various head coverings.
Head coverings in modern times are mostly associated with Muslim women. Some Christian and Jewish women also wear headscarves.
The hijab was originally worn as a gesture of modesty, though some women also use it to publicly identify themselves as Muslim.
“There are Arab or Muslim women who choose to wear the hijab as an expression of their cultural identity,” according to the website Arabs in America.
Still others choose not to wear the hi