matter
/ˈmætə/
As a noun referring to substance, it evokes the tangible, heavy reality of the physical world. It is the clinical term for "stuff," stripped of specific identity or quality. When used as a noun for a subject or situation, it carries a tone of formality and gravity. Calling something a "matter" rather than a "problem" or "topic" often suggests a professional, legal, or serious context that requires resolution. As a verb, it describes the weight of significance. It is frequently used in the negative ("doesn't matter") to dismiss triviality or express indifference, creating a contrast between what is consequential and what is irrelevant.
Uncountable when discussing the physical stuff that makes up the universe ('dark matter'). Countable when referring to a specific topic, problem, or legal case ('a private matter').
Meanings
Physical substance in general, as distinct from mind and spirit; substance of which a thing is composed.
"Scientists are studying the properties of dark matter."
A subject or situation under consideration.
"I will discuss this matter with my lawyer before making a decision."
To be of importance or significance.
"It doesn't matter which color you choose; they both look great."