Definition of ink-cap:
(n) :
A pigment (or dye)-based fluid used for writing, printing etc.
(n) :
(countable) A particular type, color or container of this fluid.
(v) :
(transitive) To apply ink to; to cover or smear with ink.
(v) :
(transitive) To sign (a contract or similar document).
(v) :
(transitive) To apply a tattoo to (someone).
(n) :
The black or dark-colored fluid ejected by squid, octopus etc, as a protective strategy.