A structure formed of straight wood or metal members between points (or nodes) on a circular sphere (or part thereof) that are “pinned” at each connection point to two or more other members that transfer loads imposed on the structure to the base of the structure. The geometric areas between individual members may support a “skin” if the structure is to be enclosed. A “regular” geodesic structure have members of equal length but strengths of members may vary depending on location in the geodesic “grid”.

Source: https://en.wikipedia.org/wiki/Glossary_of_architecture