red dog

from the GNU version of the Collaborative International Dictionary of English.

• The lowest grade of flour in milling. It is dark and of little expansive power, is secured largely from the germ or embryo and adjacent parts, and contains a relatively high percentage of protein. It is chiefly useful as feed for farm animals.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Used other than as an idiom: see red,‎ dog.
• noun US, American football A blitz.
• verb US, American football To blitz.