oyster thief; pocket thief; brown algae (Colpomenia sinuosa)
A species of brown algae that forms hollow, bladder-like sacs. The English common names 'oyster thief' and 'pocket thief' refer to its tendency to envelop small objects. Used in biological and culinary contexts.
Oyster thief is a brown algae that grows attached to rocks in the intertidal zone.
Around here, they sometimes put oyster thief in miso soup.
Katakana spelling is standard for this seaweed name; usually written in kana.
Kanji spelling is rare; the word is usually written in kana.
From 袋 (fukuro, 'bag') + 海苔 (nori, 'seaweed'), referring to its hollow, sac-like shape. The exact historical derivation is uncertain.