Painting as an activity has been with us for 32,000 years and that's longer than any written language. Many of the terms artists use to describe their work come from France or Italy where the technical aspects of oil paint really developed. Here are some that can help make sense when talking about a painting or understanding the work of other artists.
Chiaroscuro - Italian - literally this translates to "light dark" and was widely employed by Renaissance artists for 3d modeling of the human figure, and grew into the method of starting a painting in a monochrome. These masters preferred a neutral color, usually an earth tone.The painting was then developed using glazing over this.
Glazing - In oil painting, the simplest form of a glaze is a thin, oily, transparent layer of paint spread over the top of an opaque passage that has been given some time to dry. This allows great control of color and value. This is akin to a transparent wash in watercolor.
Imprimatura - Italian - Renaisannce artists discovered that a painting in monochrome was facilitated by painting either a stain or a flat field of a single color over the whole area of the painting (canvas, panel or even a wall!)
Gesso-(pronounced "JESSO") - Italian and Latin - is a traditional mix of a binder (any one of numerous vehicles, from acrylic polymer to hide glues made from animal products) chalk, and a white pigment , used to coat rigid surfaces such as wooden panels as an absorbent primer substrate for painting.
Camera obscura - Latin - is an optical device that projects an image of its surroundings on a flat field (Canvas, wall, panel, etc) so that I can be drawn or painted.
Impasto - Italian - refers to thick paint that displays brush strokes or knife marks. This is very difficult to do well and can express speed, texture, or a record of action in painting.
Alla prima - Italian or Premier Coup-French - meaning all at once (in one attempt). Usually this is a form of wet-into-wet technique where the complete painting is created in one sitting.
Pointillism - technique where the whole painting is created by using small, separate and distinct dots of paint to create the whole painting
Faux painting or faux finishing - two terms that describe a decorative paint finish , when done properly duplicate the way materials such as granite, marble, (stone), pine, maple, oak, walnut, (wood )aluminum, steel, silver and gold (metals) are the chief textures portrayed, but almost any material or texture is fair game.
Tromp L'oeil - French - (deceive the eye) is a painting approach using very realistic imagery to create the illusion that depicted objects exist in three dimensions (the original trick 3d). It can be so life like that people try to scrape the $10 bill off the canvas or brush away a fly!
Plein-Aire (or En Plein Aire) - French - "in the open air" and refers to painting out of doors or in the open. Many of the French Impressionists employed this to create vibrant paintings with intense effects of light and color.
Fresco - Italian - (meaning "fresh") A form of mural painting into wet plaster, using water based paints mostly composed of pure pigment.