DS>  > Customer: I.ll have a martini, dry.
 DS>   If I'm not mistaken, in this case, dry means "bitter". I think of what

I don't even know why I know this, except to the extent that I was once
confused by that term, too.  A dry martini is a martini which has very little
vermouth added to it.

Found this:

Legend has it that Sir Winston Churchill liked his Martinis served without
the vermouth actually being added to the drink, just present in the same
room. He is quoted as saying of the drink, "Glance at the vermouth bottle
briefly while pouring the juniper distillate freely."
--- Mystic BBS v1.12 A46 2020/08/26 (Linux/64)