blind spot noun 1. a.: the point in the retina not sensitive to light where the optic nerve passes through the inner coat of the eyeball — see eye illustration b.: a portion of a field not seeable or inspectable with available equipment < one limitation of radar is the existence of blind spots at low levels > 2.: an area in which one fails to exercise understanding, judgment, or discrimination 3.: a locality in which radio reception is markedly poorer than in the surrounding area