D defs.my
Entry 1 sense Webster, 1913

Incertum

· In·cer·tum · IPA
01 a. Doubtful; not of definite form.
  1. 1.
    Doubtful; not of definite form.
Phrases & compounds
Opus incertum — a kind of masonry employed in building walls, in which the stones were not squared nor laid in courses; rubblework.