Noun

(en noun)

The person, place or thing from which something (information, goods, etc.) comes or is acquired.

* {{quote-book, year=2006, author=(Edwin Black)

, title=Internal Combustion, chapter=2 citation , passage=More than a mere source of Promethean sustenance to thwart the cold and cook one's meat, wood was quite simply mankind's first industrial and manufacturing fuel.}}

* {{quote-magazine, date=2013-07-06, volume=408, issue=8843, page=68, magazine=(The Economist)

, title= The rise of smart beta , passage=Investors face a quandary. Cash offers a return of virtually zero in many developed countries; government-bond yields may have risen in recent weeks but they are still unattractive. Equities have suffered two big bear markets since 2000 and are wobbling again. It is hardly surprising that pension funds, insurers and endowments are searching for new sources of return.}}

Spring; fountainhead; wellhead; any collection of water on or under the surface of the ground in which a stream originates.

* {{quote-magazine, date=2013-08-16, author= John Vidal

, volume=189, issue=10, page=8, magazine=(The Guardian Weekly) , title= Dams endanger ecology of Himalayas , passage=Most of the Himalayan rivers have been relatively untouched by dams near their sources . Now the two great Asian powers, India and China, are rushing to harness them as they cut through some of the world's deepest valleys.}}

A reporter's informant.

(computing) Source code.

(electronics) The name of one terminal of a field effect transistor (FET).

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.