MVP
Also known as: minimum viable product
An MVP is the smallest version of a product that can be put in front of real users to test whether the idea works. Its purpose is learning, not saving money — though it usually does that too.
The word doing the work is viable. An MVP has to be genuinely usable for one complete job, end to end, and be good enough that a person's reaction to it is informative. A half-built version of everything teaches nothing except that it is half-built.
The discipline is choosing the one thing. Every feature that seems obviously necessary is a candidate for the second release, and the point of the exercise is to discover which of them the users never mention.