In a bahuvrīhi samāsa in the chandas (Vedas) a word of two syllables with acute accent (udātta) on the first syllable when preceded by su gets acute accent (udātta) on the first syllable.,
In other words, such a word retains its accent. Thus:- स्वश्वा॒॒सिन्धुः॑ सु॒॒रथा॑ सु॒॒वासा॑ (Rig Veda X. 76. 8). Here स्व꣡श्वः and सुर꣡थः have acute on अ and र, which they had originally also, for अश्व and रथ are formed by क्वन् (Unadi I. 151) and क्थन् (Unadi II. 2) respectively and have the नित् accent (VI. I. 197). Why do we say 'having acute on the first syllable'? Observe या सु॑बा॒॒हुः स्व॑ङ्गुरिः (Rig II. 32.7). Here बाहु has acute on the final (Unadi I. 27 formed by उ affix and has the accent of the affix 3.1.3). Why do we say 'having two syllables'? Observe सुगुरसत्, सुहिरण्यः ॥ This sutra is an exception to 6.2.172.,