अर्थे

Thus मात्रे इदं = मात्र॑र्थम्, देव꣡तार्थम्, अ꣡तिथ्यर्थम् ॥ The words मातृ and पितृ are finally acute as taught so in Unadi sutra (Unadi II. 95): देवता being formed by a लित् affix 5.4.27 has acute on the middle; अतिथि is formed by इथिन् affix and has acute on the first.

The difference between तदर्थ and अर्थ is that the former, like दारु 'wood', हिरण्य 'gold', has not inherent in it the sense of adaptibility, while अर्थ means 'adapted'. Some say that the making of two sutras, one with तदर्थ and the other with अर्थ indicates, that the former rule is applicable only to that compound where the material itself is changed into the substance of the first. Therefore the rule does not apply to अश्वघासः꣡, श्वश्रूसुरम् &c, though 'grass be suited for the horse' &c.,