The phrase "rice husk" refers to the outer protective covering of rice grain. It is the tough outer layer that needs to be removed before consuming rice. Full definition
For example, Tata has created a home water purifier that uses rice husk ash impregnated with nano - silver to filter out bacteria and viruses. (educationworld.com)
Extracted from rice husk, this oil's naturally high smoke point of 232 °C (450 °F) makes it ideal for high temperature cooking like stir - fry (urmatt.com)
«We have already done tests with rice husk ash and the results are very positive. (sciencedaily.com)