noun

• The cavity or mold in which anything is formed.
• (now rare) The womb.
• The metaphorical place where something is made, formed, or given birth.
• (biology) The material or tissue in which more specialized structures are embedded.
• (biology) An extracellular matrix, the material or tissue between the cells of animals or plants.
• (biology) Part of the mitochondrion.
• (biology) The medium in which bacteria are cultured.
• A table of data.
• (mathematics) A rectangular arrangement of numbers or terms having various uses such as transforming coordinates in geometry, solving systems of linear equations in linear algebra and representing graphs in graph theory.
• (computing) A two-dimensional array.
• (electronics) A grid-like arrangement of electronic components, especially one intended for information coding, decoding or storage.
• (geology) A geological matrix.
• (archaeology, paleontology) The sediment surrounding and including the artifacts, features, and other materials at a site.
• (analytical chemistry) The environment from which a given sample is taken.
• (printing, historical) In hot metal typesetting, a mold for casting a letter.
• (printing, historical) In printmaking, the plate or block used, with ink, to hold the image that makes up the print.
• (dyeing) The five simple colours (black, white, blue, red, and yellow) from which all the others are formed.
• (material science) A binding agent of composite materials, e.g. resin in fibreglass.
• (science fiction) A simulated reality to which many humans are connected. In some works created by sentient machines to subdue humans.
• (figurative) A social institution or apparatus perceived as largely deceptive or illusory.
• (slang, figurative, science fiction) Alternative letter-case form of Matrix; a controlled environment or situation in which people behave in ways that conform to pre-determined roles. [(science fiction) A simulated reality to which many humans are connected. In some works created by sentient machines to subdue humans.]