An empty place changed arithmetic
In a place-value numeral system, a digit’s position determines its value: the 5 in 50 means five tens, while the 5 in 5 means five ones. But a system like this needs a way to mark an empty position. Without a zero in 507, for example, the number could be mistaken for 57.
Indian mathematicians developed a place-value system that used zero as a placeholder and, over time, treated it as a number that could be calculated with. Arabic-language scholars adopted and developed this mathematics. The Arabic word ṣifr—“empty”—became the name associated with zero as the system moved into Europe.
One root, two English words
As the term passed through European languages, its forms split. One branch led to zero, the familiar name for the number. Another led to cipher, first associated with the zero sign and then more broadly with written numerals or codes. The connection survives in the word’s double sense: a cipher can be a system for concealing a message, but it can also mean a person or thing with little apparent significance.
The mathematical meaning was anything but insignificant. A symbol for an empty place made positional notation practical for recording large numbers and carrying out calculations. The same idea that let a scribe distinguish 507 from 57 helped make arithmetic more compact—and left English with two words descended from the language of “empty.”
