A book that teaches the alphabet; a primer.

(simile) Extremely easy

(usually capitalized) Soil that has a well-differentiated profile, with the three types or horizons of soil.

plural of ABC book

(number theory) Given coprime positive integers a, b and c, such that a + b = c, and d the radical of abc (the product of its distinct prime factors), the conjecture that d is usually not much smaller than c (in other words, that if a and b are divisible by large powers of primes, then c usually is not).

A minimalist style of visual art.

plural of ABC soil

A U.S. television news channel.

(military) Initialism of airborne battlefield command and control center.

(biology) On the side facing away from the chalaza of a seed.