[pen.e.tra.tion] n (1605) 1 a: the power to penetrate; esp: the ability to discern deeply and acutely b: the depth to which something penetrates c: the extent to which a commercial product or agency is familiar or sells in a market
2: the act or process of penetrating: as a: the act of entering a country so that actual establishment of influence is accomplished b: an attack that penetrates the enemy's front or territory syn see discernment