A pile of rocks.
A headstone marking a person's grave.
The symbol "∎" marking the end of a proof.
A crashdump.
A marker that takes the place of deleted data, allowing for replication of the deletion across servers etc.
An unusual morphological feature on an electrocardiogram indicative of acute myocardial infarction, characterized by a massive ST elevation.
A printed advertisement in a newspaper or magazine, typically having unadorned centered text in black and white, enclosed in a simple box.
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.
To replace (an object or data) with a tombstone marker.
To take part in tombstoning: to jump into the sea, etc. from a cliff or other high point so as to enter the water vertically straight.