To
erase,
obliterate, or
remove. To cause
something to enter a
state of
nonexistence. Often used of
data.
Also a key on the PC keyboard which usually deletes the character to the right of the cursor.
On the Macintosh keyboard, the key marked "delete" is what a PC user would call a backspace key, and is in the position for such; the key marked "del" is a PC-style delete key.