the smallest possible quantity
the limit on the lower (or southernmost) side of something
The lower limit of a sequence of real numbers is the real number which can be found as follows: remove the first term of the sequence in order to obtain the "first subsequence." Then remove the first term of the first subsequence in order to obtain the "second subsequence." Repeat the removal of first terms in order to obtain a "third subsequence," "fourth subsequence," etc. Find the infimum of each of these subsequences, then find the supremum of all of these infimums. This supremum is the lower limit.