DefaultDuration is an option to Animate and related functions that specifies the default total duration of the animation in seconds.
Denominator[expr] gives the denominator of expr.
Expression is a symbol that represents an ordinary Mathematica expression in Read and related functions.
FeedbackType is an option for some control system functions that specifies the feedback type.
LegendAppearance is an option for charting functions that specifies the appearance of any legends that are generated.
LogicalExpand[expr] expands out logical combinations of equations, inequalities, and other functions.
Modulus
(Built-in Mathematica Symbol) Modulus -> n is an option that can be given in certain algebraic functions to specify that integers should be treated modulo n.
NotebookObject[fe, id] is an object that represents an open notebook in the front end.
Numerator[expr] gives the numerator of expr.
PolynomialRemainder[p, q, x] gives the remainder from dividing p by q, treated as polynomials in x.