In Earthsea one character often has several names.
This is because in Earthsea, the true name of a person has power, and a wizard can wield total power over someone whose name he knows. Consequently, any person guards his true name closely, and only shares it with those whom he or she can totally trust. Through childhood up to puberty, children are known by a child-name; at their rite of Passage, about the age of thirteen, children are given a true name in the Old Speech, usually by a wizard, that they will keep for the rest of their lives. In the Kargad lands this is not done, and a name given to a child functions as that person’s name for life; it may, or may not, be the person’s true name.
In dealings with most people, the Hardic peoples of Earthsea use a “use-name”, usually a common word in the Hardic language (rendered into English) by which they are identified. Use-names are often words referring to animals (Dragonfly, Goha, Hare, Hawk, Hound, Lark, Murre, Otak, Otter, Sparrowhawk, Tern), plants (Alder, Apple, Aspen, Beech, Hemlock, Heather, Ivy, Lily, Littleash, Moss, Rose, Rowan, Vetch, Yarrow), stones and other substances (Diamond, Flint, Golden, Ivory, Jasper, Onyx); but some are simply sequences of sound without obvious meaning.
A person may keep one use-name all his or her life, or may change it at whim, or may be known to one group of people by one name, and to others by another name. While each true name only refers to one person, use-names may be shared by several people;
via Characters in Earthsea – Wikipedia, the free encyclopedia.