didymos?
There is no prefix for it. Usually this is tuplet like octuplet.
it means "new" didymos means "twin". so element 60- neodymium means new twin
Hypnosis is from the Greek root Hypnos, the Greek personification of sleep whose twin was Thánatos, or death.
The name Thomas is the Greek form of the Aramaic name תָּאוֹמָא (Ta'oma') which meant "twin".In Hebrew, the word for twin is te'om (תאום).
Didymus ia a medical term for one of the testes. It is also related to the Greek word for twin didymos.
Castor and Pollux
The Greek name of Apollo's twin is Artemis. She is the goddess of the hunt, wilderness, and wild animals in Greek mythology.
Apollo and Artemis are twin Greek gods.
Artemis
The Swedish word for twin is tvilling.
Mahanga is the kupu Māori for twin.
Artemis