Keywords are widely-used mechanisms for classifying technical endeavour, especially papers in journals, bibliographies, and private collections. However their effectiveness is limited if the set of keywords contains many synonyms: for instance "Z-buffer" and "depth buffer". In general, overlaps are more complicated than this, and designing a consistent set takes a long time. G-words is a unique set of over 700 carefully selected keywords, logically structured in a hierarchy (an acyclic directed graph) and covering geometric computing topics across CAD, CAGD, CAM, computational geometry, computer graphics, computer vision and GIS. The book is divided into two sections. The first section is an alphabetic list of keywords, with a glossary and redirection pointers from common synonyms. The second section is a traversal of the hierarchy, with pointers back into the first list. Using these two sections together, the best keywords to describe a particular paper or other piece of work can be rapidly selected.