What does the word "Comprehension" mean in the Axiom of Comprehension? I understand roughly what the Axiom of Comprehension means, that any predicate can be used to construct a set of the elements that satisfy the predicate. But in English terms, where does the word "Comprehension" come from? I assume it is from "comprehensive", as in "covering everything," or something of that ilk, and not "comprehension" as in "understanding." Can anyone explain the connection to the usual English meanings of the word?

The relevant sense of _comprehend_ is ‘to include, comprise, or encompass’, which is indeed the sense reflected in the adjective _comprehensive_. The axiom schema of comprehension allows us to form sets that _comprise_ or _include_ all elements of a given set that have some particular property. (It’s also called the axiom schema of specification: we form sets by _specifying_ a property that their members must satisfy.)