Refers to the dark liquid produced by squid, used in cooking (e.g., pasta, risotto) or as a defense mechanism.
See also: イカ墨
I like pasta made with squid ink.
When a squid senses danger, it squirts out squid ink.
Standard modern spelling using katakana for イカ and kanji for 墨.
Kanji spelling for イカ; rarely used in modern writing.
Compound of イカ (squid) + の (possessive particle) + 墨 (ink).