Source: A 1931 dictionary
Dhār (धार्) is the Nepali word for the edge of a blade.1
Lagāunu dhār (लगाउनु धार्); to give an edge, sharpen. Lagāunu literally means: To put on, wear (clothes); arrange, fix, set up, plant.
For a complete overview of khukurī terminology, see my article: A Nepalese khukurī glossary.
1. Sir Ralph Lilley Turner; A comparative and etymological dictionary of the Nepali language. London: K. Paul, Trench, Trubner, 1931.