base

"Base" is a versatile word, but all its meanings usually circle the same core sense: an underlying support.

At its most concrete level, it refers to the lowest supporting part of something—the base of a mountain, a statue, a lamp, or even a tree trunk. In chemistry, a base is a substance that reacts with acids, often by accepting protons, as part of acid-base chemistry where it changes a solution's character.

It also means the fundamental component of a combination, such as tomato sauce as the base for many pasta dishes. In a more abstract sense, the noun can stand for the main group people connected to something—think of a politician’s voting base, a sports team’s fan base, or an organization’s customer base.

As a verb, "to base" means to use something as the foundation for what you make. "The artist based her painting on old photographs." "The report should be based on reliable evidence."

In mathematics, the base of a number system (like base-10, the one we use most) determines how numbers are written and counted. In baseball, "base" is one of the four points a player must touch to score. In the military and everyday speech, a base can mean a home base for operations, the place from which action is organized.

At times, "base" is used as an adjective for behavior or motives that are morally low: "base instincts," "base actions." So, whether it means support, starting point, group foundation, or moral quality, it usually points to what lies underneath and gives a thing its core.