1) Philosophical doctrine 2) Philosophical theory 
Logicism is one of the schools of thought in the philosophy of mathematics, putting forth the theory that mathematics is an extension of logic and therefore some or all mathematics is reducible to logic. Bertrand Russell and Alfred North Whitehead championed this theory, created by mathematicians Richard Dedekind and Gottlob Frege. Dedekind`s pat....
theory that mathematics can be derived from a set of logical axioms
school of mathematical thought introduced by the 19th–20th-century German mathematician Gottlob Frege and the British mathematician Bertrand ... [9 related articles]
one of the schools of thought in the philosophy of mathematics, putting forth the theory that mathematics is an extension of logic and therefore all mathematics is reducible to logic.[5] Bertrand Russell and Alfred North Whitehead championed this theory fathered by Gottlob Frege. Frege gave up on the project after Russell recognized a paradox expos...
[n] - the philosophical theory that all of mathematics can be derived from formal logic
noun (philosophy) the philosophical theory that all of mathematics can be derived from formal logic
the doctrine, developed chiefly by Gottlob Frege and Bertrand Russell, that mathematics can be reduced to logic.
the theory that mathematics is just an extension of logic, and that therefore some or all mathematics is reducible to logic