“erat”

The following 2 entries include the term erat.

quod erat demonstrandum

Latin phrase

: which (is what) was to be shown (originally) —abbreviation QED —used at the end of a logical or mathematical proof

See the full definition

quod erat faciendum

Latin phrase

: which (is what) was to be done (originally) —abbreviation q.e.f. —used at the end of a geometrical construction

See the full definition

Word of the Day

Listen to the pronunciation of boondoggle

See Definitions and Examples »

Test Your Vocabulary

Challenging Words You Should Know

  • hedgehog reading a book
  • Often used to describe “the march of time,” what does inexorable mean?
Name That Thing

You know what it looks like… but what is it called?

TAKE THE QUIZ
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.

Pick the best words!

PLAY
Love words? Need even more definitions?

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

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
girl-playing-trumpet
Sound Check: A Musical Word Quiz Tune-up your vocabulary
See All