Wave Set Cephus

Cardi B and Offset's baby boy Wave Set Cephus can thank his rapper father for his super cool first name. Sources connected tell TMZ ... the Migos rapper was the one who came up with the name Wave. Once Cardi and Offset knew they were having a boy, we're told they started throwing around words and…

It took 8 months, but Cardi B and Offset are finally revealing their baby boy's name and showing him off to the world -- so get ready to meet Wave Set Cephus!!! The proud parents both posted pics Thursday of their little bundle of joy, already iced out in Cuban link chains ... with Offset…