Noun

(en noun)

Someone who , especially someone hired to show people around a place or an institution and offer information and explanation.

The guide led us around the museum and explained the exhibits.

* Bible, Psalms xlviii. 14

He will be our guide , even unto death.

A document or book that offers information or instruction; guidebook.

A sign that guides people; guidepost.

Any marking or object that catches the eye to provide quick reference.

A device that guides part of a machine, or guides motion or action.

# A blade or channel for directing the flow of water to the buckets in a water wheel.

# A grooved director for a probe or knife in surgery.

# (printing, dated) A strip or device to direct the compositor's eye to the line of copy being set.

(occult) A spirit believed to speak through a medium.

(military) A member of a group marching in formation who sets the pattern of movement or alignment for the rest.

Noun

(en noun)

Subject; theme; a category or general area of interest.

*{{quote-magazine, date=2013-08-03, volume=408, issue=8847, magazine=(The Economist)

, title= The machine of a new soul , passage=The yawning gap in neuroscientists’ understanding of their topic is in the intermediate scale of the brain’s anatomy. Science has a passable knowledge of how individual nerve cells, known as neurons, work. It also knows which visible lobes and ganglia of the brain do what. But how the neurons are organised in these lobes and ganglia remains obscure. Yet this is the level of organisation that does the actual thinking—and is, presumably, the seat of consciousness.}}

(Internet) Discussion thread.

(obsolete) An argument or reason.

* Bishop Wilkins

contumacious persons, who are not to be fixed by any principles, whom no topics can work upon

(obsolete, medicine) An external local application or remedy, such as a plaster, a blister, etc.

(Wiseman)