Definition of leetspeak in English:

leetspeak

(also 1337speak)

noun

mass noun
  • An informal language or code used on the Internet, in which standard letters are often replaced by numerals or special characters that resemble the letters in appearance.

    ‘users communicated in leetspeak’

Origin

1990s: from leet + -speak. The form 1337speak represents the conventions of leetspeak, with 1 representing the letter L and 3 and 7 representing the letters E and T respectively..

Pronunciation

leetspeak

/ˈliːtspiːk/