the.com/unmarked
The deliberate absence of a flag, which is itself a kind of flag.
means Bearing no identifying sign, label, or distinction — or, in grammar, the default form that needs no special signal.
from From the Old English 'mearc' (boundary, sign) with the negating prefix 'un-' — literally lacking the line drawn to set something apart.
Linguist favoriteDefault forms count as unmarked: actor versus actress.
Police paradoxAn unmarked car everyone instantly recognizes as unmarked.
Math meaningUngraded work, the homework purgatory of teachers.