Ghosts don't actually have names. Most of them are referred to simply as "Ghost". The few that DO have names are named by their Guardians. For example, Felwinter named his ghost Felspring. Ikora named hers Ophiucus. Cayde called his Sundance. Presumably Osiris named Sagira. Crow's ghost was given the nickname "Pulled Pork" as the butt of some joke we arent privy to. It didn't have a real name until Crow named it Glint. There's also some precedent for Ghosts naming their Guardians too since most never learn their original living names. Felwinter was named by his Ghost who presumably knew that he was actually an echo of Rasputin. Glint gave Crow his name after Spider suggested it so that he never learns who he was. Ana happened to be wearing her ID badge for Dr. Anastasia Bray so she is a rare special case that learned her real name from the beginning. We actually know of a few Guardians original names that they themselves do not know. For example the Emissary of The Nine was formerly an Awoken Guardian called Orrin and before that an Awoken member of the Queen's court called Nasan Ar. Before she became Awoken she was a colonist aboard the Exodus Green and was named Nasya Sarwar. At least one Guardian was never named by his Ghost and never took a liking to a particular name of his own. He was known as Wu Ming and later as Eli and later still as Dredgen Hope. We know him now as Drifter. The point is names often change in the lore. I do hope at some point Glint reveals where the nickname came from. I'm sure it's quite a story.