The word "芥茉" is formed by combining two characters, both containing the grass radical "艹" to denote plant-related meanings. "芥" incorporates the phonetic component "介" to suggest pronunciation and signifies mustard plants, while "茉" uses the phonetic component "末" for sound and typically refers to jasmine, but here it is employed phonetically to represent the "mo" sound in mustard, resulting in a compound that functionally indicates mustard despite the irregular character choice.