A data-processing operation similar to a merge, except that instead of producing a sequence of items made up from the input sequences, the sequences are matched against each other on the basis of some key.

1. A charge of gunpowder put in a paper several inches long and used for igniting explosives.

2. A short flammable piece of wood, paper, or other material tipped with a combustible mixture that bursts into flame through friction.

To select blood donors whose erythrocytes are compatible with those of the recipient.

See <<biconditional operation>>