Pelagia noctiluca, also known as the purple stinger [Photo © Hans Hillewaert CC BY-SA 4.0]

jelly

/ ˈdʒɛli / noun

a sea creature with a soft, rounded, almost transparent body:
Jellies have a bad reputation, but they don’t all sting.

Scientists prefer the term jelly, but jellyfish is the more common term:
I got stung by a jellyfish.

In Australia they are also called stingers:
The stinger season has arrived off the Queensland coast.

The space probe Juno entered the Jovian orbit in July 2016.

Jovian

/ ˈdʒoviən / adjective

Jovian is used to refer to things that are connected with the planet Jupiter:
The Jovian atmosphere consists largely of hydrogen and helium.