In (usually US) English there is a printing term slug and its subsequent newspaper use:
- A slug is a single line of type from the days of hot metal typesetting. Prior to this a "slug" was a spacing line of metal; also has a more general meaning of "lump", usually of metal.
- In the Linotype era, the practice in newspapers was to put an identifying line of type, a slug, at the top of galley with a working title or code name, so they could easily identify each story (or separately typeset piece of the story). Older reference works also use the term "catch line" as well as "slug" (Newspaper Editing, Grant Milnor Hyde, 1931, p89)
- Hence it came to be used as the working title or code name for a newspaper story. The OED gives "an identifying title, usually occupying one slug [line of type], accompanying a news story in draft and galleys."
- The slug is never intended to be in print, it is just for the editors and compositors during the process of production, functioning a little like a filename in digital production.
A typical sentence would be Reporter: "What slug should I use for this murder story?" Editor: "Use 'MOB KILLING'". It's usually a noun but sometimes used as a verb: "Slug it 'MOB KILLING'"
Surely Spanish typesetters called the line of type something, and surely they had a similar practice of labelling galley.
What should we use in Spanish for the printing and journalism term? Did Spanish printers use the English word "slug" for a line of type? Or perhaps lingote, as used in Spanish Wikipedia under Linotipia Did news editors use titulo, clave or something along those lines for the working title of a news story?
Here's an article about how they use "working title" slugs at the New York Times, with illustration of a "typesetting" slug.
Here's a few "working title" slugs at the top of book galley:
My dictionaries only give the "bullet" meaning of slug: bala, posta and counter/token/coin meaning (ficha), none of which seem appropriate. I see bala de entintar for inking ball, so seems it's not used in printing for the slug.
French Wikipedia uses the English word slug for the "working title" link and ligne-bloc link for "line of type". As noted above, lingote, is used in Spanish Wikipedia under Linotipia for "cast line of type", but perhaps that is just explanation for how it's made. (We certainly wouldn't use English ingot for this.)