matter

(noun): Substance, material.
(noun): A condition, subject or affair, especially one of concern.
(noun): An approximate amount or extent.
(noun): The essence; the pith; the embodiment.
(noun): Inducing cause or reason, especially of anything disagreeable or distressing.
(noun): Pus.
(verb): To be important.
(verb): (in negative constructions) To care about, to mind; to find important.
(verb): To form pus or matter, as an abscess; to maturate.

What's the matter?; state matters
I stayed for a matter of months.
Sorry for pouring ketchup on your clean white shirt! - Oh, don't worry, it does not matter.