Hans mors namn var Eileen Prince, och hans far var en Muggle (Tobias Snape). Således gav han sig namnet "Halvblodsprinsen":
'I was going through the rest of the old Prophets and there was a tiny announcement about Eileen Prince marrying a man called Tobias Snape, and then later an announcement saying she'd given birth to a-'
'-murderer,' spat Harry.
'Well...yes,' said Hermione, 'So...I was sort of right. Snape must have been proud of being "half a Prince", you see? Tobias Snape was a Muggle from what it said in the Prophet.'
'Yeah, that fits,' said Harry. 'He'd play up the pure-blood side so he could get in with Lucius Malfoy and the rest of them.'
Half-Blood Prince Chapter 30: "The White Tomb"
Det anges aldrig om någon annan kände honom med det här namnet, men med tanke på hans Slytherins ursprung och det faktum att Voldemort stod upp, är det osannolikt att han berättade för andra studenter om hans halvblodsstatus.
Tja, kanske en annan student ...