I would say that "infinity" is more a quality than a thing. Infinity is a concept that changes with what you are talking about. If you are talking about time when you say infinity you mean unending time, if you are talking about space, then you mean unending space, if you are talking mathematics then you mean an unending count of whatever concept you are talking about, such as the infinite number of integers.

Checking my dictionary (Websters' II New Riverside University Dictionary, 1984) I find that infinity is a noun, (1) "The quality or state of being infinite".

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.