The affix tasi comes in the sense of 'in the same direction with that'.,
This ordains another affix in addition to the previously taught अण् &c ञ &c. The words formed by this affix are Indeclinables (I. I. 37). Thus हिमवतः 'in the same direction as Himavat.' पीलुमूलतः, सुदामतः ॥,