What is a sentence that uses every letter of the alphabet called?
'The quick brown fox jumps over the lazy dog' is a famous example.
The best-known English pangram, 'The quick brown fox jumps over the lazy dog', has been used for well over a century to test typewriters, teleprinters and fonts, because one line shows every letter of the alphabet. It is 35 letters long, so some letters (such as o, e, h, r and u) repeat. The Library of Congress holds a printed item bearing the sentence, and Merriam-Webster calls it the most famous example of the form.
The word 'pangram' is built from Greek roots meaning 'all' and 'letter'. Pangrams in the ordinary sense only require that each of the 26 letters appears at least once; there is no limit on repeats. A 'perfect pangram' uses each letter exactly once, which forces the author into odd, abbreviation-heavy or invented-word phrases, and such lines are far harder to make read naturally than the fox sentence. Shorter, imperfect pangrams that still make sense are a popular challenge among word-game fans.
Pangrams are easier to produce than many people expect, and they turn up by accident in ordinary writing. Merriam-Webster notes that lexicographer Jesse Sheidlower built a bot that finds and reposts pangrams that people tweeted without noticing. Other languages have their own versions, since each alphabet has its own set of letters to cover. The exact first appearance of the fox sentence is murky, and claims about who coined it should be treated cautiously.