execution

Here the thing carried out is a sentence of death. The phrase "as a penalty" is what separates this use from killing in general, so the word fits judicial and state contexts. By extension it also covers the acts and arrangements surrounding the penalty. It sits close to enforcing a court judgment, since both carry a court's decision into effect.

Behind every sense of the word stands Latin exsequor, "to follow out": ex "out" plus sequor "follow", reaching English through Old French. To give a plan execution is to follow it out to the end. The phrase put into execution keeps that older shape, and John Ormsby's 1885 Don Quixote has the knight "set himself forthwith to put his scheme into execution." The noun can also judge how well something was done, as with a gymnast's execution.

A trap for non-lawyers: executing a contract means making it binding, typically through signing and delivery, not performing what it promises. Execution comes at the start of the agreement's legal life, and the obligations still lie ahead once it is complete. The same language applies to deeds, where execution can wait on conditions such as cleared funds.

In law the word usually takes of plus its object: the execution of a judgment, the execution of a will. For a judgment it means enforcing the court's orders. For a will it means settling the estate as the will directs. Making a contract binding is a different act, because it brings a document into force rather than carrying one out.

Computing applied the general idea of carrying something out to the processor, which works through a program's instructions in sequence. The word covers whole programs, parts of programs and single instructions alike, and it combines readily, as in execution time. Execution is what happens when code runs. Writing and compiling the code come before it, and an error can halt it partway.