EdgeStyle is an option and property for Graph and related functions that specifies what style to use for edges.
Element
(Built-in Mathematica Symbol) Element[x, dom] or x \[Element] dom asserts that x is an element of the domain dom. Element[{x_1, x_2, ...}, dom] asserts that all the x_i are elements of dom. Element[patt, ...
EllipticNomeQ[m] gives the nome q corresponding to the parameter m in an elliptic function.
E
(Built-in Mathematica Symbol) E is the exponential constant E (base of natural logarithms), with numerical value \[TildeEqual] 2.71828.
Epilog
(Built-in Mathematica Symbol) Epilog is an option for graphics functions that gives a list of graphics primitives to be rendered after the main part of the graphics is rendered.
Equivalent[e_1, e_2, ...] represents the logical equivalence e_1 \[DoubleLeftRightArrow] e_2 \[DoubleLeftRightArrow] ..., giving True when all of the e_i are the same.
EulerGamma is Euler's constant \[Gamma], with numerical value \[TildeEqual] 0.577216.
EventLabels is an option to CandlestickChart, KagiChart, and similar functions that specifies events to labels.
ExactNumberQ[expr] returns True if expr is an exact real or complex number, and returns False otherwise.
ExpandDenominator[expr] expands out products and powers that appear as denominators in expr.