Webster's Revised Unabridged Dictionary · 1913

A B C

A B C (ā bē sē")

1.
The first three letters of the alphabet, used for the whole alphabet.
2.
A primer for teaching the alphabet and first elements of reading. [Obsolete]
3.
The simplest rudiments of any subject; as, the A B C of finance.
Collocations (1)
A B C book , a primer. — Shakespeare