A white person.
A salty cookie.
"What cracker is this same that deafe our eares with this abundance of superfluous breath?" —- William Shakespeare, King John, Act II, Scene 1, 1594.
"Death to racist crackers!" — graffiti on a bathroom wall, University of Florida, 1969.
As those quotations show, the word cracker is burdened with several centuries’ worth of bad connotations. At least when the word is applied to people instead of being served with soup... continued on "What's a Cracker?"