Other forms: ingrained; ingrains; ingraining
To ingrain is to deeply and strongly establish something within a person, particularly a belief or habit. You may hate those daily algebra quizzes, but they ingrain a routine of reviewing some math every night.
In the 14th century, this verb (originally spelled engrain) was used to mean "dye a fabric red with cochineal." It comes from the French en graine, where graine means "seed or berry," the source of a deep and permanent dye. To ingrain something is to fix it permanently, the way a great teacher ingrains good study habits in his students, or your distant friend's photo helps ingrain her face in your mind.