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Everything about Epsilon

Fifth letter of the Greek alphabet

Epsilon is the fifth letter of the Greek alphabet, corresponding phonetically to a mid front unrounded vowel IPA: [e̞] or IPA: [ɛ̝]. In the system of Greek numerals it also has the value five. It was derived from the Phoenician letter He (𐤄‎). Letters that arose from epsilon include the Latin E, Ë and Ɛ, and Cyrillic Е, È, Ё, Є and Э. The name of the letter was originally εἶ, but it was later changed to ἒ ψιλόν in the Middle Ages to distinguish the letter from the digraph ⟨αι⟩, a former diphthong that had come to be pronounced, and because the digraph ⟨ει⟩ had become unsuitable due to its own shift to. In Modern Greek, its name has fused into έψιλον. Wikipedia →

🧭 Start here: a 6-step reading path

  1. Read the overview: EpsilonA 5-minute orientation
  2. Skim a recent paper: Flexible polystyrene/graphene composites with epsilon-near-zero propertiesInfluential work since 2022
  3. Pick up a classic book: The sixth general catalogue of Sigma alpha epsilonThe most-reprinted book on the subject
  4. Read the landmark paper: THE ELECTRODYNAMICS OF SUBSTANCES WITH SIMULTANEOUSLY NEGATIVE VALUES OF $\epsilon$ AND μCited 9,716 times
  5. Go sideways: SigmaA closely related topic
  6. Go sideways: PhiA closely related topic

📖 Definitions

Noun The fifth letter of the Greek alphabet, ε or Ε, preceded by delta (Δ, δ) and followed by zeta (Ζ, ζ).

Noun In IPA, the phonetic symbol ɛ that represents the open-mid front unrounded vowel.

Noun An arbitrarily small quantity. (Can we verify this sense?) A small child.

Noun (Can we verify this sense?) A small child.

🗂️ The subject at a glance

  1. History
  2. Uses
  3. Unicode
  4. Initial

🏆 Landmark papers (most cited)

🆕 Influential since 2022

📚 Books worth reading

Ranked by number of editions on Open Library, a rough measure of how lasting a book is.

🔗 Related topics