What does 3rd person omnicient mean?

Third person narration means telling a story through the use of personal pronouns "he," "she," "they," etc. Therefore the narrator is not necessarily one person and the story can be told by different characters. Third person omnicient means the narrator can get into the heads of all characters and know everything happening at all points of the story, instead of sticking with the place and time that one character is occupying. In this viewpoint the narrator often is not one of the characters but just an unnamed teller of the story.