(US, education, uncountable) A school (in the US, middle school) course that introduces students to concepts needed to learn algebra.
2000, Alfred S. Posamentier, Making Pre-Algebra Come Alive, Sage Publications (Corwin Press), page 1,
In most secondary school curricula, pre-algebra is the last course in which specific attention is paid to multiplication, division, squares, cubes, and primes. Thereafter, these skills and operations are pretty much taken for granted.
(mathematics, countable) A particular form of Lie algebra; also applied analogously to other types of algebra.
2006, Oswald Wyler, Algebraic Theories of Continuous Lattices, Bernhard Banaschewski, Rudolf-Eberhard Hoffmann (editors), Continuous Lattices, Springer, Lecture Notes in Mathematics 871, page 398,
Let mathsf f:( mathsf A,α)→( mathsf B,β) be a morphism of prealgebras.