Bhuvana means a world, a sphere, the inhabited space of existence, and Bhuvaneshvari is its ishvari, its ruler. The tradition presses that further than a title of authority usually goes. She is not principally described as a deity who made the world, or who governs it from outside; the texts describe the world as her body. Space is her, the elements are her, the directions are her limbs, and the cosmos is what she looks like.
Her image is benign. She is red or golden, three-eyed, crowned with the crescent moon, and four-armed, holding a noose and a goad and making the gestures of granting boons and of dispelling fear. The noose and goad she shares with Tripura Sundari, and the two are frequently paired as the gentle face of the set, over against Kali, Tara, Chhinnamasta and Dhumavati.
Her seed syllable is hrim, called the maya bija, and the association is deliberate: what is spread out as the visible world is also what conceals what underlies it. That gives her a philosophical position rather than a story. Hymns to her, including the Bhuvaneshvari stotras preserved in the tantras, work by enumeration rather than by narrative, listing what she is until the list has covered everything there is, which is a different literary method from the ones used for the fierce members of the group.