geometry UK /d͡ʒiːˈɒm.ɪ.tɹi/US /d͡ʒiˈɑ.mə.tɹi/ noun4 •The branch of mathematics dealing with spatial relationships.ANY problem in geometry can easily be reduced to such terms that a knowledge of the lengths of certain straight lines is sufficient for its construction. — 1925 •A mathematical system that deals with spatial relationships and that is built on a particular set of axioms; a subbranch of geometry which deals with such a system or systems.Entire new geometries are also suggested by real-world cities. — 1975 •The observed or specified spatial attributes of an object, etc.The inset of figure 1 shows the geometry of the samples. They are 4.6 mm long and 0.4 mm wide. — 1990 •A mathematical object comprising representations of a space and of its spatial relationships. formsgeometries