jellyfish
n.a sea animal with a soft, clear body that looks like jelly and long, thin tentacles. Some of them can give you a painful sting if you touch them.
n.a free-swimming marine coelenterate with a gelatinous bell- or saucer-shaped body and stinging tentacles. Often used as a collective noun when referring to a group in a biological context.
“We saw a large jellyfish floating near the shore.”
“The beach was closed to swimmers after several people reported being stung by a jellyfish in the shallow water.”
“While most species are harmless to humans, the translucent body of the box jellyfish contains a potent venom that can cause severe physiological distress within minutes of contact.”
The plural form can be either 'jellyfish' or 'jellyfishes', though 'jellyfish' is more common when referring to a group of the same species.
Etymology tree Proto-Indo-European *gel- Latin gelū Proto-Indo-European *-h₂ Proto-Indo-European *-éh₂ Proto-Indo-European *-yéti Proto-Indo-European *-eh₂yéti Proto-Italic *-āō Latin -ō Latin gelō ▲ Proto-Indo-European *-éh₂ Proto-Indo-European *-tós Proto-Indo-European *-eh₂tos Proto-Italic *-ātos Latin -ātus Latin -āta Early Medieval Latin gelāta Old French geleebor. Middle English gele English jelly Proto-Indo-European *péysks Proto-Germanic *fiskaz Proto-West Germanic *fisk Old English fisċ Middle English fisch English fish English jellyfish From jelly + fish. From being an aquatic creature (i.e. fish) that is gelatinous (“jelly”). Despite the name, jellyfish are not biologically classified as fish. The term appeared in the mid-19th century and displaced various older terms such as sea jelly (now much less common), blubber/sea blubber, nettle/sea nettle (both now referring to specific jellyfish species), and, in scientific literature, medusa.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.