LineBreakWithin is an option for selections that specifies whether line breaks occur automatically when the end of a line is reached.
LinkConnect["name"] connects to a MathLink link created by another program.
ListPlay[{a_1, a_2, ...}] creates an object that plays as a sound whose amplitude is given by the sequence of levels a_i.
MedianDeviation[list] gives the median absolute deviation from the median of the elements in list.
symbol::tag is a name for a message.
MinusPlus[x] displays as \[MinusPlus]x.MinusPlus[x, y, ...] displays as x \[MinusPlus] y \[MinusPlus] ....
NCache
(Built-in Mathematica Symbol) NCache[x, xn] represents a numeric cache object for a quantity with exact value x and approximate numerical value xn.
Negative[x] gives True if x is a negative number.
NonNegative[x] gives True if x is a non-negative number.
O
(Built-in Mathematica Symbol) O[x]^n represents a term of order x^n. O[x]^n is generated to represent omitted higher-order terms in power series. O[x, x_0]^n represents a term of order (x - x_0) n.