Noun

(-)

The rubbing of one object or surface against another.

* {{quote-magazine, year=2013, month=July-August, author=(Henry Petroski)

, title= Geothermal Energy , volume=101, issue=4, magazine=(American Scientist) , passage=Energy has seldom been found where we need it when we want it. Ancient nomads, wishing to ward off the evening chill and enjoy a meal around a campfire, had to collect wood and then spend time and effort coaxing the heat of friction out from between sticks to kindle a flame.}}

Conflict, as between persons having dissimilar ideas or interests; clash.

(physics): A force that resists the relative motion or tendency to such motion of two bodies in contact.

* 1839 , (Denison Olmsted), A Compendium of Astronomy Page 95

Secondly, When a body is once in motion it will continue to move forever, unless something stops it. When a ball is struck on the surface of the earth, the friction of the earth and the resistance of the air soon stop its motion.

Noun

(en noun)

A barrier that has parallel or crossed bars blocking a passage but admitting air.

A frame of iron bars to hold a fire.

The loose material that comes from something being grated.

Add a few gratings of nutmeg to the hot milk.

An optical system of close equidistant and parallel lines or bars, especially lines ruled on a polished surface, used for producing spectra by diffraction.

(nautical, in the plural) The strong wooden lattice used to cover a hatch, admitting light and air; also, a movable lattice used for the flooring of boats.