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