Number & MeasureGreek → English
Epsilon
/ˈɛpsɪlɒn/noun
The fifth letter of the Greek alphabet, used in mathematics for an arbitrarily small quantity.
The Greek roots
ἒ ψιλόν
e psilón
bare e
Literally: “plain e”
Follow a root:ἒ ψιλόν1 word
The story of the word
By Byzantine times the letter ε and the digraph αι sounded identical, so scribes needed a way to say which one they meant: this was the bare e, ἒ ψιλόν. ψιλός means stripped or smooth, and it also names the breathing mark that tells you a Greek vowel carries no h. Mathematics later turned the letter into a noun for smallness itself, in the epsilon-delta definition of a limit, and Paul Erdős, who lived in that notation, called small children epsilons.
- How it travelled
- Ancient Greek → Latin → English
Same family
omicronupsilonpsilocybin
In a sentence
For any epsilon you name, I can find a point past which the difference is smaller.