noun
General term for squid and cuttlefish; in everyday contexts, usually refers to squid.
今夜はイカの刺身を食べよう。
Let's have squid sashimi tonight.
イカは足が10本ある。
Squid have ten tentacles.
Ateji kanji form; rarely used in modern writing.
タコ (octopus) has eight arms and a round body, while イカ has a more elongated body and ten arms.
The origin is uncertain. The kanji 烏賊 is ateji and does not reflect the word's derivation.