The act of one who, or that which, backtracks; a retracing of one's steps.
The usage of a runway as a taxiway, especially at private strips and smaller airports.
The act of building all possible solutions to a problem incrementally, abandoning any candidate solution if it cannot lead to a valid solution.
The act of one who undertakes (in either sense).
A promise or pledge; a guarantee.
That which is undertaken; any business, work, or project which a person engages in, or attempts to perform; an enterprise.
The business of an undertaker, or the management of funerals.