Definition of "tombstone"
tombstone
/tuːmstəʊn/
noun
plural tombstones
(cardiology) An unusual morphological feature on an electrocardiogram indicative of acute myocardial infarction, characterized by a massive ST elevation.
verb
third-person singular simple present tombstones, present participle tombstoning, simple past and past participle tombstoned
(surfing) For a surfboard to stand upright half-submerged in the water (like a tombstone, above) because the surfer is underwater with his or her legrope pulled tight. Often this indicates a surfer in difficulty, either held down by the power of a wave or unconscious and unable to get to the surface.