(rak) noun
1. An open grating, framework, or the like, in or on which articles may be placed, as a frame to hold dishes, a tier or row of pigeonholes, or a framework to hold fodder for horses, cattle, or sheep.
2. A triangular frame for arranging the balls on a billiard table.
3. A device in an airplane for carrying bombs: also bomb rack.
4. Mech. A bar or the like having teeth that engage with those of a gearwheel, pinion, or worm gear.
5. A machine for stretching or making tense; especially, an intrument of torture which stretches the limbs of victims.
6. Torture or punishment as by the rack; hence, intense mental or physical suffering.
7. A wrenching or straining, as from a storm.
—v.t.
1. To place or arrange in or on a rack.
2. To torture on the rack.
3. To cause suffering to; torment.
4. To strain, as with the effort of thinking: to rack one's brains.
5. To raise (rents) excessively: see RACK–RENT. ♦ Homophone: wrack. [ME rekke, prob. <MDu. rec, recke <recken stretch]
—rack′er noun

(rak) noun
The single-foot.
—v.i. To proceed or move with this gait. ♦ Homophone: wrack. [? Var. of ROCK²]

(rak) noun
1. Thin, flying, or broken clouds.
2. Any floating vapor.
—v.i. To move rapidly; send, as clouds before the wind. Also spelled wrack. [<Scand. Cf. ON rek drifting wreckage, reka drive, drift.]

(rak) noun
Wrack; wreck; demolition: obsolete except in the phrase “to go to rack and ruin.” [Var. of WRACK²]

v.t.
To draw off from the lees, as liquor. ♦ Homophone: wrack. [<Provençal arracar <raca refuse of grapes]
RACK AND PINION