自动零位器
Nullifier \Nul"li*fi`er\, n. One who nullifies or makes void; one who maintains the right to nullify a contract by one of the parties.
nullifier n 1: an advocate of nullification; someone who believes that a state can resist federal laws 2: an official who can invalidate or nullify; "my bank check was voided and I wanted to know who the invalidator was" [syn: {invalidator}, {voider}]