What is "to put one's nose to the grindstone"

Grindstone \Grind"stone`\, n. A flat, circular stone, revolving on an axle, for grinding or sharpening tools, or shaping or smoothing objects. To hold one's nose to the grindstone, To bring one's nose to the grindstone, to oppress one; to keep one in a condition of servitude. To put one's nose to the grindstone

1. to oppress one; to cause one to work hard and steadily.

2. to set oneself to a long and arduous task.

   To keep one's nose to the grindstone to continue at a long and arduous task; to apply oneself steadily to one's duties.

   They might be ashamed, for lack of courage, to suffer the Laced[ae]monians to hold their noses to the grindstone.
   --Sir T. North.

Nose \Nose\ (n[=o]z), n. [AS. nosu; akin to D. neus, G. nase, OHG. nasa, Icel. n["o]s, Sw. n["a]sa, Dan. n["a]se, Lith. nosis, Russ. nos', L. nasus, nares, Skr. n[=a]s[=a], n[=a]s. [root]26

1. Cf. Nasal, Nasturtium, Naze, Nostril, Nozzle.] 1. (Anat.) The prominent part of the face or anterior extremity of the head containing the nostrils and olfactory cavities; the olfactory organ. See Nostril, and Olfactory organ under Olfactory.

2. The power of smelling; hence, scent.

   We are not offended with a dog for a better nose than his master.
   --Collier.

3. A projecting end or beak at the front of an object; a snout; a nozzle; a spout; as, the nose of a bellows; the nose of a teakettle. Nose bit (Carp.), a bit similar to a gouge bit, but having a cutting edge on one side of its boring end. Nose hammer (Mach.), a frontal hammer. Nose hole (Glass Making), a small opening in a furnace, before which a globe of crown glass is held and kept soft at the beginning of the flattening process. Nose key (Carp.), a fox wedge. Nose leaf (Zo["o]l.), a thin, broad, membranous fold of skin on the nose of many species of bats. It varies greatly in size and form. Nose of wax, (fig.), a person who is pliant and easily influenced. ``A nose of wax to be turned every way.'' --Massinger Nose piece, the nozzle of a pipe, hose, bellows, etc.; the end piece of a microscope body, to which an objective is attached. To hold one's nose to the grindstone, To put one's nose to the grindstone, or To bring one's nose to the grindstone. See under Grindstone. To lead by the nose, to lead at pleasure, or to cause to follow submissively; to lead blindly, as a person leads a beast. --Shak. To put one's nose out of joint, to humiliate one's pride, esp. by supplanting one in the affections of another. To thrust one's nose into, to meddle officiously in. To wipe one's nose of, to deprive of; to rob. [Slang] on the nose,

   1. exactly, accurately.

   2. (racing) to win, as opposed to to place or to show.