阿基米德立体是一种高度对称的半正多面体，且使用两种或以上的正多边形为面的凸多面体，并且都是可以从正多面体经过截角、截半、截边等操作构造。阿基米德立体的每个顶点的情况相同，共有13种。阿基米德曾研究半正多面体（虽然其研究纪录已佚），故有人将半正多面体唤作阿基米德立体。因为面是由正多边形组成的，每个相邻的正多边形的边长相等，故阿基米德立体的边均有相同长度。阿基米德立体的对偶多面体是卡塔兰立体。

半正多面体一词不只是指13种阿基米德立体，而是指所有具有对称群且由2种或2种以上正多边形所组成的多面体。

In geometry, an Archimedean solid is a highly symmetric, semi-regular convex polyhedron composed of two or more types of regular polygons meeting in identical vertices. They are distinct from the Platonic solids, which are composed of only one type of polygon meeting in identical vertices, and from the Johnson solids, whose regular polygonal faces do not meet in identical vertices.