Full Idea
Supervaluationists take a present-tense predication as concerning a single, but vaguely specified, moment. …It is indeterminate which of a range of moments enters into the truth conditions, but it is true if satisfied by every member of the range.
Gist of Idea
Supervaluation refers to one vaguely specified thing, through satisfaction by everything in some range
Source
Katherine Hawley (How Things Persist [2001], 2.7)
Book Reference
Hawley,Katherine: 'How Things Persist' [OUP 2004], p.58
A Reaction
She is discussing stage theory, but this is a helpful clarification of the idea of supervaluation. Something can be satisfied by a whole bunch of values, even though you are not sure which one.