Cyanea purpurea is a species of true jellyfish in the family Cyaneidae.

The generic name, Cyanea, is derived from the Latin cyaneus, meaning "deep or dark blue in color".

The specific epithet, purpurea, is derived from the Latin purpureus, meaning "purple", in reference to its violet color.

Cyanea purpurea has a disc-shaped bell around 36 centimetres (14 in) in diameter.

The margin of the bell consists of 16 broad lobes.