1. A fine or very thin thread or fiber: filaments of cloth; filaments of flax.
2. A slender or threadlike structure or part, especially:
a. A fine wire that is heated electrically to produce light in an incandescent lamp.
b. The stalk that bears the anther in the stamen of a flower.
c. A chainlike series of cells, as in many algae.
d. A long thin cellular structure characteristic of many fungi, usually having multiple nuclei and often divided by septa.
e. Any of various long thin celestial objects or phenomena, such as a solar filament.
[New Latin fīlāmentum, from Late Latin fīlāre, to spin, from Latin fīlum, thread; see gwhī- in the Appendix of Indo-European roots.]
fil′a·mentous (-mĕntəs), fil′a·menta·ry (-mĕntə-rē, -mĕntrē) adj.
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.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus