1 a manually operated device to correct the operation of an automatic device
2 the act of nullifying; making null and void; counteracting or overriding the effect or force of something [syn: nullification]
1 rule against; "The Republicans were overruled when the House voted on the bill" [syn: overrule, overturn, overthrow, reverse]
2 prevail over; "health considerations override financial concerns"
3 counteract the normal operation of (an automatic gear shift in a vehicle)