When a set of several words ending with case-affixes stands in a relation expressable by 'and' the set is made into a compound and the compound so formed is called dvandva,
The meanings that may be indicated by च 'and' are four, (1) समुच्चयः 'community of reference,' (2) अन्वाचय 'collateralness of reference, (3) इतरेतरयोगः 'mutual conjunction' and (4) समाहारः 'aggregate.' In the first two cases viz., community of reference, and collateralness of reference, composition does not take place, because the words are not directly related to one another (II. I. I). Composition is enjoined therefore, when the sense of च is that of mutual conjunction and lumping. Thus we cannot compound ईश्वरं गुरुं च भजस्व 'reverence God and thy Guru' or भिक्षामट गां चानय 'go for alms and bring the cow.' But we can compound the following प्लक्षश्च न्यग्रोधश्च = प्लक्षन्यग्रोधौ 'the Plaksha and the Nyagrodha trees.' So धव-खदिर-पलाशाः , वाक्त्वचम्, वाग्दृषदम् ॥,