原子簇化学（英语：cluster chemistry）是当前化学中最有趣而又极其活跃的领域之一，首先由弗兰克·阿尔伯特·科顿于1966年提出，对研究生命科学、材料科学、有机金属化学等领域都有很重要的意义。***将clusters译为“原子簇”，将cluster compound译为“原子簇化合物”，而把transition metal cluster译为“过渡金属簇合物”。

原子簇有多种定义，比较全面的是由徐光宪、江元生等人提出的定义：

In chemistry, a cluster is an ensemble of bound atoms or molecules that is intermediate in size between a molecule and a bulk solid. Clusters exist of diverse stoichiometries and nuclearities. For example, carbon and boron atoms form fullerene and borane clusters, respectively. Transition metals and main group elements form especially robust clusters. Clusters can also consist solely of a certain kind of molecules, such as water clusters.