It's spelled "lede" so as not to be confused with "lead," as in the metal with which was used to print newspapers.
Since "lead" (as in beginning of a story) and "lead" (as in metal) were frequently used in print newsrooms, the spelling of one changed over time to reduce confusion.
There were a number of other language convolutions in newsrooms, such as "slug" which meant a piece of hot metal, and so was useful for describing a spent bullet, the very short text that served as a title for a particular story, and a section of metal letters on the printing press.
/Worked for two major newspaper companies back when printing newspapers was akin to printing money.
“TK” meaning “to come” is another one. “More TK” in particular is now a blogger affectation but it seems to have been a way to communicate to an editor that a story was so far incomplete, within the text of a submission, without the editor assuming the words “to come” were part of the story. And elsewhere it indicates a placeholder that needs a fact to be confirmed and filled in before publication.