Most of the races are named after wives of Kaśyapa. For example,
Descendants of Aditi: Adityas (Devas)
Descendants of Danu: Danavas
Descendants of Diti: Daityas
Origin of Rakshasas is different which is described here.
Though Danavas, Daityas and Rakshasas are used interchangeably or collectively (as demon or asura) but they are different.
As per Śrīmad-...