What does the Greek letter Epsilon ἑ stand for?

Epsilon ἑ (ε) is the fifth letter of the Greek alphabet. It represents the sound "e" and has a numerical value of 5. In the system of Greek numerals, it has a value of 8. Epsilon is also used to represent a particular type of error in statistics, as well as the error term in a Taylor series. In mathematics, it is sometimes used to represent an arbitrarily small quantity.