lamb·​da | \ ˈlam-də How to pronounce lambda (audio) \

Definition of lambda

1 : the 11th letter of the Greek alphabet — see Alphabet Table
2 : an uncharged unstable elementary particle that has a mass 2183 times that of an electron and that decays typically into a nucleon and a pion

Examples of lambda in a Sentence

Recent Examples on the Web

It is divided by the upside-down V of the Greek lambda, the sigil falsely believed to have been painted on Spartan shields at Thermopylae. Myke Cole, The New Republic, "The Sparta Fetish Is a Cultural Cancer," 1 Aug. 2019 The Xi decays into a particle called the lambda baryon and three lighter particles, the K- (or kaon) and two pions. Fox News, "‘Charming’ heavy particle discovered at world’s largest atom smasher," 11 July 2017 However, the name is trademarked, and the project opted instead for lambda — the Greek letter used to symbolize wavelength. Wired Staff, WIRED, "Fast Track for Science Data," 17 Nov. 2003

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lambda.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of lambda

15th century, in the meaning defined at sense 1

History and Etymology for lambda

Middle English, from Greek, of Semitic origin; akin to Hebrew lāmedh lamed

Keep scrolling for more

Learn More about lambda

Statistics for lambda

Last Updated

6 Aug 2019

Look-up Popularity

Time Traveler for lambda

The first known use of lambda was in the 15th century

See more words from the same century

Keep scrolling for more

More Definitions for lambda


lamb·​da | \ ˈlam-də How to pronounce lambda (audio) \

Medical Definition of lambda

1 : the point of junction of the sagittal and lambdoid sutures of the skull

More from Merriam-Webster on lambda Encyclopedia article about lambda

Comments on lambda

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


a period when something is suspended

Get Word of the Day daily email!

Test Your Vocabulary

Summer 2019 Words of the Day Quiz

  • a-bowl-of-peach-sorbet-with-cut-peaches-next-to-it
  • Which is a synonym of desideratum?
Spell It

Can you spell these 10 commonly misspelled words?

Word Winder's CrossWinder

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

Love words? Need even more definitions?

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