Ear1  n. 1 organ of hearing, esp. Its external part. 2 faculty for discriminating sounds (an ear for music).  3 attention, esp. Sympathetic (give ear to; have a person's ear).  all ears listening attentively. Have (or keep) an ear to the ground be alert to rumours or trends. Up to one's ears (often foll. By in) colloq. Deeply involved or occupied. [old english]