1. A standardized, often interchangeable component of a system or construction that is designed for easy assembly or flexible use: a sofa consisting of two end modules.
2. Architecture A length used as a unit of measurement or as a standard for determining the proportions of a building.
3. Electronics A self-contained assembly of electronic components and circuitry, such as a stage in a computer, that is installed as a unit.
4. Computers A portion of a program that carries out a specific function and may be used alone or combined with other modules of the same program.
5. A self-contained unit of a spacecraft that performs a specific task or class of tasks in support of the major function of the craft.
6. A unit of education or instruction with a relatively low student-to-teacher ratio, in which a single topic or a small section of a broad topic is studied for a given period of time.
7. Mathematics An algebraic system that resembles a vector space, except that the set of scalars forms a ring and not necessarily a field.
8. Biology A unit of modular growth, such as a coral polyp.
9. Archaic A standard or unit of measurement.
[Latin modulus, diminutive of modus, measure; see med- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.