algebra (n.)

Algebra comes from the Arabic al-jabr, out of the title of a book al-Khwarizmi wrote in Baghdad in the ninth century, Hisab al-jabr w’al-muqabala.¹

Al-jabr is restoring, or reuniting what is broken. In the book it names a particular move: a term subtracted on one side is restored by adding it to the other, until the equation balances.¹²

The everyday sense travelled with the word. When algebra first came into English in the sixteenth century it could still mean the surgical setting of a fracture, and in Spanish an algebrista was a bone-setter.³

The same book gave the other word. Algorithm came out of the author’s name.¹

He teaches algebra to first-year students.