The Collaborative International Dictionary of English v.0.48:

Balder \Bal"der\ (b[add]l"d[~e]r), prop. n. [Icel. Baldr, akin
   to E. bold.] (Scan. Myth.)
   The most beautiful and beloved of the gods; the god of peace;
   the son of Odin and Freya. [Written also Baldur.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Balder
    n 1: (Norse mythology) god of light and peace and noted for his
         beauty and sweet nature; son of Odin and Frigg and husband
         of Nanna; killed by Hoth [syn: Balder, Baldr]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "Balder":
   Adonis, Aesir, Aphrodite, Apollo, Apollo Belvedere, Astarte, Bor,
   Bori, Bragi, Cleopatra, Donar, Forseti, Frey, Freya, Freyja, Freyr,
   Frigg, Frigga, Hebe, Heimdall, Hel, Hertha, Hoenir, Hyperion, Idun,
   Ing, Ithunn, Loki, Nanna, Narcissus, Nerthus, Njord, Njorth, Odin,
   Reimthursen, Sif, Sigyn, Thor, Tiu, Tyr, Ull, Ullr, Vali, Vanir,
   Venus, Venus de Milo, Vidar, Vitharr, Wayland, Weland, Woden,
   Wotan, Wyrd, houri, peri, the Graces