Elisserion is the supposed name of a gigantic Egyptian unicorn. D. J. Conway attributes information about it to Brunetto Latini, but it appears to be nonexistent.
According to Bartholomeus Anglicus, there are three kinds of unicorns:
- the rhinoceros, which, according to Pliny, is the size of an elephant but has shorter legs. It has one horn on its nose.
- the monoceros, with the body of a horse, the head of a stag and the feet of an elephant.
- the egloceron, whose name is garbled αιγόκερως and means "capricorn", very small and similar to a kid. The name was rendered by Jules Berger de Xivrey in French as "eglisseron". This creature was first described in the book called the Physiologus, written in the second century in Alexandria in Christian Egypt.
The elisserion was likely born by merging the descriptions of the rhinoceros (huge size) and the egloceron.