Art Terms and Definitions — O

art words descriptions

Art words and descriptions that begin with the letter “O”. The list below with more than 10 terms begins OCTAPTYCH and ends with OVERPAINTING.

Quick links to more art words and descriptions are located at the end of the list.

Art Words and Descriptions: “O” Words


An artwork consisting of eight panels or sections where each panel depicts a different but related composition. The panels can be hinged together or presented side-by-side to make one large image. The term “octaptych” is not a widely used, although it is used in the visual arts. It comes from the Greek words “octa” (meaning “eight”) and “ptychos” (meaning “fold” or “layer”). Also see “polyptych.”

Oil Paint

An art medium used by artists since the 1500s. Oil paint is a slow-drying medium made from ground pigment suspended in a natural drying oil, which is usually linseed oil, but can also be walnut or poppyseed oil. It can be applied thick or thin and can be used with glazes. Oil paint’s slow drying makes it easier to blend from dark to light, creating three-dimensional illusions. Its richness and glow make it popular among painters. Clean-up involves using turpentine or mineral spirits.

Oil Painting

still life oil painting
Still Life with Coral and Lantern by Teresa Bernard

An artistic composition or representation done with oil paints on a canvas surface. Also refers to the art or practice of painting with oil paints. Oil painting artists are often referred to as painters. Some of the most famous oil painters in history include Leonardo da Vinci, Michelangelo Buonarotti, Vincent van Gogh, Johannes Vermeer, and Rembrandt van Rijn.

Oiling Out

A technique where a thin layer of oil is applied to a dried layer of oil paint to make it more flexible and workable. This process allows for better color blending, smoother transitions, and a uniform surface. Oiling out evens the painting surface’s sheen so that the artist may determine what work needs to be done to finish the painting. It also helps to improve the saturation of an oil painting, reviving it if it appears dull or less saturated. After oiling out is finished, painting can be resumed or left to dry.

Old Master

A term that refers to a prominent and highly skilled European artist, especially a famous painter during the period roughly 1300–1830. Also refers to a painting by such an artist.

On-chain Art

A type of digital art called NFTs (non-fungible tokens) that is created using generative algorithms that are coded and completely stored on a blockchain. This enables the development of one-of-a-kind, verifiable digital artworks, as well as a secure and transparent method of verifying the artwork’s authenticity and tracking its ownership history.

One-point Perspective

art words and descriptions
One-point Perspective

The simplest method of drawing perspective. It uses only a single vanishing point on the horizon line. A vanishing point is where two or more parallel lines converge into each other at “infinity.” A long hallway, railroad track, or road with the viewer positioned face-on and looking down the center is an excellent example of this perspective. As seen in the illustration, the two tracks are parallel to each other, and you know they will remain the same distance apart. However, the further away they get, the closer they appear to be until they eventually disappear at the horizon.

Op Art (optical art)

An art movement which emerged in the 1960s that used optical illusions to confound and excite the eye. Op art, short for “optical art,” is an abstract style of visual art that uses bold colors or black-and-white geometric patterns and lines. Precision mathematics, stark contrast, and abstract shapes are frequently used to give the viewer a sense of movement, hidden images, flashing and vibrating patterns, or swelling or warping. Not to be confused with pop art.

Open Composition

open composition with balloons
Up, Up, and Away! by Teresa Bernard is a good example of open composition.

A compositional technique where elements of an image run off the edges and seemingly beyond the boundaries of the canvas, drawing the viewer inside the scene making it easy to imagine what is happening outside of the physical edges of the artwork. Landscapes are prime examples of open compositions.

An open composition is the opposite of “closed composition.”

Optical Mixing

Also known as partitive color, this phenomenon occurs when two or more colors placed near each other create the illusion of new colors. Unlike traditional color mixing, which involves physically mixing pigments to create new colors, partitive color occurs perceptually, between our eyes and our brain. The perceived mixing increases with distance.


art words descriptions

One of the secondary colors created when the two primary colors of red and yellow are mixed. The complement or opposite of the color blue. The color of carrots, pumpkins, sweet potatoes, oranges, and many other fruits and vegetables.


The Japanese art of folding paper into shapes that look like birds, animals, etc. The object is to transform a flat square sheet of paper into a finished sculpture through folding and sculpting techniques.


The term ‘original’ can imply exclusivity or the idea that the work is ‘one of a kind’ rather than a copy by any method, including offset lithography, digital printing, or forgery. Not all paintings can be considered original since the term also refers to the newly created image, so a painted copy of another work is not an original.

Orthogonal Lines

Outsider Art

Refers to artwork by those outside of mainstream society. Outsider art broadly includes folk art, ethnic art, and art by prisoners, the mentally ill, and others neither trained in art nor making their works to sell them.

Overlap Effect

A technique used by artists to create a sense of depth and space within the compositions of their drawings or paintings. This is done by deliberately positioning objects so that some objects or elements are partially hidden from view by one or more closer object. When one object hides or overlaps a portion of another, it creates a visual hierarchy, indicating which elements are in front and which are behind making the scene more interesting and three-dimensional.


The final layer of paint that is applied over the underpainting (or underlayer) after it has dried. The idea behind layers of painting is that the underpainting serves to define the main outlines and design of the piece, allowing the overpainting to fill in the details.

You May Also Like

This art words and descriptions is provided as a valuable resource for art enthusiasts. If you like the information here and find it helpful, please consider purchasing a painting. Your support helps to cover the cost of keeping this art words and descriptions lexicon online. Simply click or tap the thumbnail link of any Teresa Bernard oil painting to view additional details.

snail art
Snail #2: Left Hanging (2021)
6″ w x 6″ h
space art
Space…The Next Frontier (2017)
24″ w x 18″ h

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Contributing to The Art Dictionary

The glossary of art words and descriptions is a work in progress. New terms and definitions are added on a regular basis. If you know of an art term and definition that isn’t already listed in it but you believe it should be, send it to us and we’ll consider adding it. We’ll let you know if we do. Thanks!

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