The word substrate can mean the following:

• In biochemistry, a substrate is a molecule which is acted upon by an enzyme.
• In industrial printing, substrate is used to describe the base material that images will be printed onto. Depending on the printing process and end use of the product, these materials include (though are not limited to) films, foils, textiles, fabrics, plastics, and any variety of paper (lightweight, heavyweight, coated, uncoated, paperboard, cardboard, etc.).
• In the semiconductor industry a substrate is a wafer of material, normally a single crystal, upon which semiconductor devices can be fabricated using epitaxial crystal growth and photolithography. Depending on the material and application the substrates can be between 5 and 30 cm in diameter. They are prepared by cutting large synthetic cylindrical crystal boules (or ingots) into slices and polishing the surface to a high degree of smoothness.
• In biology, a substrate is an environment in which an organism lives, and which it feeds on. For example, in many households, a bruised apple is a substrate for the growth of a fungus.
• In linguistics, a substrate or substratum refers to words borrowed from a language formerly spoken in a region, into the language currently spoken. For example, the French word chêne, meaning oak, is borrowed from the Gaulish language, a Celtic language formerly spoken in France.