Full Idea
The universe is a somewhat ambiguous term: it may mean all the things that exist at a single moment, or all things that ever have existed or will exist, or the common quality of whatever exists.
Gist of Idea
The 'universe' can mean what exists now, what always has or will exist
Source
Bertrand Russell (The Principles of Mathematics [1903], §442)
Book Reference
Russell,Bertrand: 'Principles of Mathematics' [Routledge 1992], p.470