Of a bha aṅga (stem) ending in an with a preceding ṣa as well as of han and dhṛtarājan , the a is elided before the affix aṇ ,
Thus औक्ष्णः, ताक्ष्णः, भ्रौनघ्नः, धार्तराज्ञः ॥ But सामनः, वैमन ॥ Why do we say before the affix अण्? Observe ताक्षण्यः ॥ Why do we say 'preceded by a ष'? Observe सामनः and वैमनः from सामन् and विमन् formed with the affix अण्; here neither the अ of मन् nor the final syllable अन् is elided, since 6.4.167 keeps these words in their primitive state so far.,