Epsilon

Epsilon (uppercase/lowercase Ε ε), is the letter of the Greek alphabet, used to represent the "e" sound in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 5. Letters that came from it include the Roman E and Cyrillic Е. It is also used in calculus to represent a very small number (particularly in proofs involving limit). In set theory, a typographical variant of epsilon can be used to represent the statement "a is a member of set A" (symbolically ${\displaystyle a\in A}$).[1]

Greek alphabet
Αα Alpha Νν Nu Ββ Beta Ξξ Xi Γγ Gamma Οο Omicron Δδ Delta Ππ Pi Εε Epsilon Ρρ Rho Ζζ Zeta Σσς Sigma Ηη Eta Ττ Tau Θθ Theta Υυ Upsilon Ιι Iota Φφ Phi Κκ Kappa Χχ Chi Λλ Lambda Ψψ Psi Μμ Mu Ωω Omega
History
Archaic local variants Diacritics Ligatures Numerals ϛ (6) ϟ (90) ϡ (900)
Use in other languages
Bactrian Coptic Albanian
Related topics
Use as scientific symbols
Book Category Commons

(A little fact: The Ypsilon is the only letter of the alphabet that you can divide into syllables: Y-psi-lon)