The word medium (from Latin, in which it means, "the one in the middle") can have different meanings in different contexts. Usually it has something to do with either a material substance, or a form of mediation.


When medium is used as the singuar of media, it can have several different meanings.

In communications and technology:

A transmission medium.
A given type of mass media.
A given type of recording medium
Interactive media
Scientific meanings:

In optics, a medium (optics) is something that is homogeneous on lengthscales comparable with the wavelength of the light being considered.
In biotechnology, a growth medium.
In chemistry, a solvent.
In biology, an environment in the middle of which an organism lives; e.g. "fish require an aqueous medium."
In medicine and paleontology, a substance in which specimens are preserved or displayed.
In astronomy, the interplanetary medium or the interstellar medium.
An excitable medium.
In art:

A liquid with which pigment is mixed by a painter.
The type of physical material with which a work of art is created. (See: Art techniques and materials.)


Certain other uses of the word medium have the plural mediums.

In everyday life a size that is in the middle (T-shirts can be S, M, L, XL or XXL) between very little and very large, average or mean in a range of sizes or conditions. Usually, one of only a few sizes, rather than many. For example, items such as clothes or drinks at a fast food restaurant might come in three sizes: small, medium, and large.
A state that is intermediate between extremes; a middle position; "a happy medium".
In parapsychology, a spiritual medium is a person who claims to serve as an intermediary between the living and the dead.

Other meanings

Medium is the title of a 2005 American television series.
MEDIUM is an Architectural design company based in Montreal Canada.


Marshall McLuhan was famous for saying "The medium is the message."