One Baghdad scholar gave us both 'algebra' and 'algorithm'

Around 820 CE, the mathematician Muhammad ibn Musa al-Khwarizmi (c. 780–850) worked at Baghdad’s House of Wisdom, an academy under Caliph al-Ma’mun that gathered and translated Greek, Persian, and Indian learning and produced original research at the height of the Islamic Golden Age.

His treatise al-Kitab al-mukhtasar fi hisab al-jabr wa’l-muqabala — “The Compendious Book on Calculation by Completion and Balancing” — laid out systematic methods for solving equations. The title names two operations. Al-jabr means restoration or completion: moving a subtracted term to the other side of an equation to make it whole. Al-muqabala means balancing: canceling equal terms on both sides. The first of these, carried into Latin in the 12th century, became our word algebra.

His methods were resolutely geometric. Lacking the negative numbers later mathematicians would use, al-Khwarizmi solved quadratics by literally completing the square — building a real square from rectangles to find an unknown length.

A second work explained the Hindu-Arabic decimal place-value system, including zero, to the West. It survives only in Latin, where al-Khwarizmi’s own name was rendered as Algoritmi. That Latin term, algorism, first meant simply doing arithmetic with these new numerals; only much later did it broaden into algorithm.

So every spreadsheet formula and every line of code carries a faint echo of a scholar working in medieval Baghdad over a thousand years ago.