- agar, nutrient agar - any culture medium that uses agar as the gelling agent
--1 is a kind of culture medium, medium
--1 has substances: agar, agar-agar
--1 has particulars: blood agar - agar, agar-agar - a colloidal extract of algae; used especially in culture media and as a gelling agent in foods
--2 is a kind of gum
--2 is a substance of agar, nutrient agar