Approximator prepositions can also apply to expressions of spatial and temporal distance (see Direction and Interval). The syntactic analysis of these constructions is not obvious; here the policy is simply to apply the label Approximator while remaining agnostic as to the precise syntax.1
#007 features a copular sentence with a preposition at the beginning of a predicate complement. In cases like this, is arguably ambiguous as to whether the preposition acts as a modifier of the quantity, which would suggest Approximator, or establishes a relation between subject and predicate, which would suggest ComparisonRef↝Locus. In general we prefer the latter analysis.
These constructions are markedly different from most PPs; it is even questionable whether these usages should count as prepositions. Without getting into the details here, even if their syntactic status is in doubt, we deem it practical to assign them with a semantic label in our inventory because they overlap lexically with “true” prepositions. ↩
An adposition that converts a point value (or pair of values) into an approximate value or range, without establishing a relation between two items/values to be compared.