What is the name for a sentence that contains all 26 letters of the alphabet?
This type of sentence is called a pangram. The most widely known pangram is the one that's traditionally been used to test typewriters or keyboards: The quick brown fox jumps over the lazy dog. Some letters in this sentence are used more than once: there's no ready example of a sentence that uses all the letters of the alphabet once only.
See other Vocabulary Questions.
See also: What is the frequency of the letters of the alphabet in English?
Or take a look at: What word contains the vowels in the right order?