directrix

noun
di·​rec·​trix | \ də-ˈrek-triks How to pronounce directrix (audio) \
plural directrixes\ də-​ˈrek-​trik-​səz How to pronounce directrixes (audio) \ also directrices\ də-​ˈrek-​trə-​ˌsēz How to pronounce directrices (audio) \

Definition of directrix

1 archaic : directress
2 : a fixed curve with which a generatrix maintains a given relationship in generating a geometric figure specifically : a straight line the distance to which from any point of a conic section is in fixed ratio to the distance from the same point to a focus

First Known Use of directrix

1622, in the meaning defined at sense 1

History and Etymology for directrix

Medieval Latin, feminine of Late Latin director, from Latin dirigere

Keep scrolling for more

Learn More about directrix

Time Traveler for directrix

Time Traveler

The first known use of directrix was in 1622

See more words from the same year

Statistics for directrix

Cite this Entry

“Directrix.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/directrix. Accessed 26 Nov. 2020.

More from Merriam-Webster on directrix

Britannica.com: Encyclopedia article about directrix

Comments on directrix

What made you want to look up directrix? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

Test Your Vocabulary

A Thanksgiving Word Quiz

  • a traditional thanksgiving dinner
  • November comes from a word for which of the following numbers?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!