e

E is the fifth letter of the Latin alphabet and one of the most common letters in English text. It functions primarily as a vowel in many languages, but can also appear as a consonant in certain digraphs. The uppercase form E is three horizontal strokes; the lowercase e is a small loop. The letter’s name in English is typically pronounced “ee.” E’s historical lineage runs from the Phoenician letter He to the Greek Epsilon and then to Latin E.

In writing and typography, E appears in many alphabets and is frequently combined with diacritics to represent additional pronunciations, such as é, è, or ê in various languages. On maps, E is commonly used to indicate the compass direction East. In the International System of Units, E serves as the symbol for the prefix exa-, meaning 10^18. In scientific notation, uppercase E is often used in computing and data representation to denote exponents, for example 1.23E4.

In mathematics and the sciences, E has several prominent meanings. Lowercase e denotes Euler’s number, approximately 2.7182818, the base of the natural logarithm and the foundation of many growth and decay models as well as the exponential function. Uppercase E commonly denotes energy, especially in physics and engineering, where E also can represent the total energy of a system. In electromagnetism, E stands for the electric field vector, a fundamental quantity describing force per unit charge.

Beyond science, E appears as a symbol in various contexts, including grammar, linguistics, and notation systems, reflecting its long-standing role in representing key concepts across disciplines.