The Collaborative International Dictionary of English v.0.48:
Guide \Guide\, n. [OE. giae, F. guide, It. guida. See Guide,
1. A person who leads or directs another in his way or
course, as in a strange land; one who exhibits points of
interest to strangers; a conductor; also, that which
guides; a guidebook.
2. One who, or that which, directs another in his conduct or
course of life; a director; a regulator.
He will be our guide, even unto death. --Ps. xlviii.
3. Any contrivance, especially one having a directing edge,
surface, or channel, for giving direction to the motion of
anything, as water, an instrument, or part of a machine,
or for directing the hand or eye, as of an operator; as:
(a) (Water Wheels) A blade or channel for directing the
flow of water to the wheel buckets.
(b) (Surgery) A grooved director for a probe or knife.
(c) (Printing) A strip or device to direct the
compositor's eye to the line of copy he is setting.
4. (Mil.) A noncommissioned officer or soldier placed on the
directing flank of each subdivision of a column of troops,
or at the end of a line, to mark the pivots, formations,
marches, and alignments in tactics. --Farrow.
Guide bar (Mach.), the part of a steam engine on which the
crosshead slides, and by which the motion of the piston
rod is kept parallel to the cylinder, being a substitute
for the parallel motion; -- called also guide, and
Guide block (Steam Engine), a block attached in to the
crosshead to work in contact with the guide bar.
Guide meridian. (Surveying) See under Meridian.
Guide pile (Engin.), a pile driven to mark a place, as a
point to work to.
Guide pulley (Mach.), a pulley for directing or changing
the line of motion of belt; an idler. --Knight.
Guide rail (Railroads), an additional rail, between the
others, gripped by horizontal driving wheels on the
locomotive, as a means of propulsion on steep gradients.