Noun
1. any instruction that works first one way and then the other; it turns something on the first time it is used and then turns it off the next time
2. a hinged switch that can assume either of two positions
3. a fastener consisting of a peg or pin or crosspiece that is inserted into an eye at the end of a rope or a chain or a cable in order to fasten it to something (as another rope or chain or cable)