Nessa is the seventh of the Queens of the Valar,
the Valie, although not an Aratar.
Dancing is her specialty, bringing joy to all. Dancing is special in Tolkien's stories, connected with power somewhat as singing is, although more as a gift of joy, expression of happiness, and attractant.
Deer are special to her, although she outruns them, and they "follow her train whenever she goes in the wild".
Orome is her brother, Tulkas her husband.
Reference: Silmarillion: "Valaquenta"
"Nessa". Artist: Olga Kukhtenkova. Rolozo Tolkien page
Image - Nessa dancing. Artist Elgaladna Shapiro. Rolozo Tolkien page.