Epsilon Symbol ε Ε
Get both uppercase (Ε) and lowercase (ε) epsilon symbols. Easy to copy and paste, with complete information about usage and typing methods.
What is the Epsilon Symbol?
Lowercase Epsilon (ε)
- Unicode: U+03B5
- HTML Code: ε
- Aliases: Small Letter Epsilon, Lunate Epsilon, Lower Case Epsilon
- Pronunciation: /ˈɛpsɪlɒn/
Description
The lowercase epsilon (ε) is the fifth letter of the Greek alphabet, representing the 'e' sound in Greek. Its form evolved from the Phoenician letter He, and it has become one of the most widely used Greek letters in various scientific fields. In modern Greek, epsilon represents the mid front unrounded vowel /e/. The symbol has gained significant importance in mathematics and sciences, where it often represents small quantities or error terms. The lowercase epsilon has two main typographical forms: - The lunate form (ε) - most commonly used in mathematics and science - The traditional form (ϵ) - sometimes used in typography and traditional Greek texts
Historical Background
Derived from the Phoenician letter He around 800 BCE, epsilon has maintained its position as the fifth letter throughout the evolution of the Greek alphabet.
Uppercase Epsilon (Ε)
- Unicode: U+0395
- HTML Code: Ε
- Aliases: Capital Letter Epsilon, Upper Case Epsilon, Capital E
- Pronunciation: /ˈɛpsɪlɒn/
Description
The uppercase epsilon (Ε) represents the capital form of the fifth letter in the Greek alphabet. In ancient Greek inscriptions, it appeared as a reversed 'E' and gradually evolved into its current form. While less commonly used in scientific notation compared to its lowercase counterpart, the uppercase epsilon maintains important roles in: - Greek language and literature - Mathematical set theory - Chemical nomenclature - Institutional logos and symbols
Historical Background
The uppercase epsilon evolved from the Phoenician He, initially written as "𐤄". Its modern form closely resembles the Latin letter E, though they developed independently.
How to Type Epsilon Symbol
Windows
Alt Code
Hold Alt and type 238 for ε (lowercase) or Alt + 917 for Ε (uppercase)
Note: Works on all Windows versions with a numeric keypad
Character Map
- Press Windows + R
- Type "charmap" and press Enter
- Select "Greek" from the Font dropdown
- Locate and double-click epsilon
- Click "Copy" to copy the symbol
Note: Useful for accessing both forms of epsilon and other Greek letters
Word/Office
- Click Insert > Symbol > More Symbols
- Select "Greek" from the Subset dropdown
- Find and select epsilon
- Click "Insert" or set up a shortcut
Note: Available in all Microsoft Office applications
Unicode Input
Hold Alt + X after typing 03B5 for ε or 0395 for Ε
Note: Works in most modern text editors and word processors
macOS
Keyboard Shortcut
Option + k for ε (lowercase)
Note: Quick and easy method for the lowercase symbol
Character Viewer
- Press Control + Command + Space
- Search for "epsilon"
- Click the desired symbol to insert
Note: Provides access to all Greek letters and variants
Greek Keyboard
- Open System Preferences > Keyboard > Input Sources
- Click + and add "Greek"
- Use the keyboard viewer to locate epsilon
Note: Useful for typing multiple Greek letters
Linux
Compose Key
Compose > e > e for ε
Note: Requires compose key setup
Unicode Input
Ctrl + Shift + U, then type 03B5 for ε or 0395 for Ε
Note: Works in most Linux distributions
Mobile Devices
iOS
- Hold down "e" on the keyboard
- Slide to select ε from the popup menu
- Alternative: Use Greek keyboard from Settings
Note: Available on iPhone and iPad
Android
- Long-press "e" on Gboard
- Select ε from the popup
- Alternative: Install Greek keyboard
Note: May vary by keyboard app and Android version
Common Uses of Epsilon Symbol
Mathematics
In mathematics, the epsilon symbol serves multiple crucial functions across different areas:
Calculus
Represents an arbitrarily small positive number in limit definitions
For any ε > 0, there exists δ > 0 such that...
Set Theory
Denotes set membership
x ∈ A means "x is an element of set A"
Analysis
Used in ε-δ definitions of limits and continuity
|f(x) - L| < ε whenever |x - a| < δ
Number Theory
Represents small error terms in approximations
π(x) = li(x) + O(x·exp(-c√(ln x)))
Physics
Epsilon plays vital roles across various branches of physics:
Electromagnetics
ε₀ represents vacuum permittivity
ε₀ ≈ 8.85 × 10⁻¹² F/m
Mechanics
Represents strain in materials
ε = ΔL/L₀ (longitudinal strain)
Thermodynamics
Denotes emissivity of materials
0 ≤ ε ≤ 1 for any real surface
Quantum Physics
Represents energy levels and states
εₙ = -13.6 eV/n² (hydrogen energy levels)
Economics
In economics, epsilon is commonly used in various analytical contexts:
Elasticity
Price elasticity of demand
ε = (ΔQ/Q)/(ΔP/P)
Econometrics
Error term in regression models
Y = β₀ + β₁X + ε
Efficiency Analysis
Technical efficiency measures
0 ≤ ε ≤ 1 for efficiency scores
Computer Science
Epsilon has several important applications in computer science:
Automata Theory
Represents empty string/transition
ε-NFA (Non-deterministic Finite Automaton with ε-moves)
Algorithms
Error tolerance in numerical computations
while |x - y| > ε do...
Machine Learning
Learning rate and convergence criteria
if loss < ε then stop training
Frequently Asked Questions
What is the difference between ε and Ε?
Why can't I see the epsilon symbol on my device?
How do I type epsilon in Microsoft Word?
What's the meaning of epsilon in mathematics?
Can I use epsilon in programming?
Is epsilon used in other fields besides mathematics?
Complete Greek Alphabet
Letter Name | Uppercase | Lowercase |
---|---|---|
Alpha | ||
Beta | ||
Gamma | ||
Delta | ||
Epsilon | ||
Zeta | ||
Eta | ||
Theta | ||
Iota | ||
Kappa | ||
Lambda | ||
Mu | ||
Nu | ||
Xi | ||
Omicron | ||
Pi | ||
Rho | ||
Sigma | ||
Tau | ||
Upsilon | ||
Phi | ||
Chi | ||
Psi | ||
Omega |
Download Epsilon Symbol Images
Lowercase Epsilon (ε)
Free for personal and commercial use. High-quality vector (SVG) and raster (PNG) formats available.
Uppercase Epsilon (Ε)
Free for personal and commercial use. High-quality vector (SVG) and raster (PNG) formats available.
Usage Rights
All epsilon symbol images are provided free of charge and can be used for both personal and commercial purposes. The SVG format is vector-based and can be scaled to any size without loss of quality. PNG format is provided in high resolution (300 DPI) for optimal display quality.