In the first half of the talk I will present the framework of nominal algebra, an algebraic framework designed to axiomatise systems with binding (such as lambda-calculus and first-order-logic) in the same way as 'ordinary' algebra axiomatises groups, rings, and fields. I will discuss applications to axiomatise substitution, lambda-calculus, and first-order logic. In the second half of the talk I will investigate a version of first-order logic based on nominal ideas (and with a semantics as a nominal algebra theory) which has strictly greater expressive power than first-order logic; I will discuss its relation to first- and second-order logic and state conservativity results with respect to first-order logic, and a cut-elimination result.