Lebesgue number
given a cover of a metric space, a positive real number δ such that any set of diameter smaller than δ is a subset of a member of the cover
en-US/ləˈbɛɡ ˈnʌmbɚ/
given a cover of a metric space, a positive real number δ such that any set of diameter smaller than δ is a subset of a member of the cover