4 Firstborn names that mean firstborn for boys, listing Firstborn baby names 1-4. Reuben and William are popular names. Cain and Primo are uncommon names. View Firstborn baby names below for name meanings.
Cain ... the firstborn son of Adam and Eve ... 
Primo ... The name may refer to the pride of a firstborn son ... 
Reuben ... Reuben was the firstborn of Jacob's 12 sons ... 
William ... The firstborn son of the current Prince of Wales is named William ...