This authority on fine food comes from the French groumet, meaning stableboy or "horse groom." Gradually, the word extended its meaning to any man-servant in a household, and then to just the steward whose cultivated taste in the kitchen led him to acquire other names of a less "stable" origin, such as epicure and connoisseur.
This three-legged frame for bearing a stretched canvas was a favorite of the Dutch masters. The upright frame bore some resemblance to a donkey, the chief beast of burden in the Netherlands. So painters transferred the name of the beast, ezel, to this common device of fortitude and patience. When the frame was adopted by English artists, the spelling changed to "easel."
When the French adopted the frame, however, they named it chevalet - referring to a "wooden horse." Sawhorse and clotheshorse are two other inventions named for their equine qualities.
This expression was first used in British horse racing in the 1700s. Usually, a horse would have to run a course several times in several "heats," such as best 2 out of 3, or best 3 out of 5. If two horses tied in a heat, the heat was thrown out, or considered "dead." Today, a dead heat is a tie, but it still may count.
Language historians trace this word's meaning to horse racing in the days of England's Queen Anne. Instead of being held within stalls at the start, horses advanced in line to a gate. A barrier of tape or webbing would be lifted away by a starter. If a horse was caught flat-footed, or not dancing on his toes when the gate rose, he'd be at a disadvantage and might lose the race.
Soon, flat-footed also applied to a runner not on his toes at the start of a race. Now the word applies to anyone who is asleep when he should be ready.
SOURCES: 'Heavens to Betsy!' by Charles E. Funk; 'The Encyclopedia of Word and Phrase Origins,' by Robert Hendrickson; 'Dictionary of Word Origins,' by Jordan Almond; 'Morris Dictionary of Word and Phrase Origins,' by William and Mary Morris, 'The Barnhart Dictionary of Word and Phrase Origins,' by Robert K. Barnhart.