Gandalf told Frodo about Gollum's history while they were at Bag End then later in the story Frodo told Gollum his true name.
Gollum. The name was given to him by his relatives, due to the "gollum" noise he made in his throat.
gollum's real name is Smeagol. he was once a hobbit like creature. but he was consumed by the power of the ring. upon acquiring it, he barely sleeps and eat and he suddenly hated the sunlight.
Sméagol was Gollum's original name.
He was named for the sound he made. It was a sort of 'gollum' sound deep in his throat.
Frodo already knew that Gollum was Smeagol because Gandalf told him earlier in the Fellowship of the Ring. When Gollum hears his old name, he realizes who he really is and that his master Frodo is the one who takes care of him now and no longer needs "Gollum".
His name is Gollum.
Smeagol.
Gollum and Smeagol are the same character. Gollum did say "My love" to Sméagol in the movies (I can't remember if he said that in the books) and considering his split-personality, perhaps it is not so surprising. It is not a term of endearment, but an eccentricity, if you will.
Gollum
Gollum
Because he is more than 300/500 years I don't remember.
gollum