半兽人或兽人（英语：Orc，Ork）是奇幻作品中的一种族，因此在此皆泛指Orc/Ork之词，也有音译为「欧克」。

关于Orc一词的来源，有说法是Orc/Ork（半兽人）由拉丁文Orcus——一位神祇的称号「阴间之王」普路同（Pluto）转变而来；Pluto在之后被直接用以称呼阴间。后来，在德文中此字以去掉原本拉丁文本尾的形态出现，成为较接近Orc的字体。

在史诗《贝奥武夫》章节ll: 112，不死的格兰戴尔的种族被称为Orc-néas，可能有“Orcus的尸体”之意。“Orcus”在罗马神话中是布鲁图（相当于希腊神话的哈底斯）或Dis Pater以外的另一个名称，代表阴间之神。这个被称为Orcus的种族似乎是死后被神以惩处恶人而烙印上邪恶与惩罚印子的种族，如同Hades（在这一层含义上还包括挪威神话Hel）。Orcus同时也可以表示衰败荒废的土地。

An orc /ɔːrk/ (also spelled as ork, orch, or yrch) is a fictional humanoid creature that is part of a fantasy race akin to goblins.

While the overall concept of orcs draws on a variety of pre-existing mythology, the main conception of the creatures stems from the fantasy writings of J. R. R. Tolkien, in particular The Lord of the Rings. In Tolkien's works, orcs are a brutish, aggressive, repulsive and generally malevolent species, existing in stark contrast with the benevolent Elvish race (from which their own ancestors were developed and corrupted) and generally pressed into the service of an evil power. Tolkien's concept of orcs has subsequently been adapted and imported into other works of fantasy fiction as well as into fantasy role-playing and strategy games (such as Dungeons & Dragons, Warhammer, and Warcraft), broadening the recognition of the creatures in popular culture.