danger triangle

noun2

1. •
   A triangular sign warning of danger.

   • 3 miles farther (9 before Kendal) there is a danger triangle on the L, “Plough Inn” on the L, and a caution board on the R of a steepish descent, and here the road forks into two. — 1908
2. •
   Ellipsis of danger triangle of the face.