Dot
(Built-in Mathematica Symbol) a.b.c or Dot[a, b, c] gives products of vectors, matrices, and tensors.
Dotted
(Built-in Mathematica Symbol) Dotted is a graphics directive specifying that lines that follow should be drawn dotted.
DoubleBracketingBar[x, y, ...] displays as \[LeftDoubleBracketingBar]x, y, ...\[RightDoubleBracketingBar].
DoubleDownArrow[x, y, ...] displays as x\[DoubleDownArrow]y....
DoubleLeftArrow[x, y, ...] displays as x \[DoubleLeftArrow] y \[DoubleLeftArrow] ....
DoubleLeftRightArrow[x, y, ...] displays as x \[DoubleLeftRightArrow] y \[DoubleLeftRightArrow] ....
DoubleLongLeftArrow[x, y, ...] displays as x\[DoubleLongLeftArrow]y\[DoubleLongLeftArrow]....
DoubleLongLeftRightArrow[x, y, ...] displays as x\[DoubleLongLeftRightArrow]y\[DoubleLongLeftRightArrow]....
DoubleLongRightArrow[x, y, ...] displays as x\[DoubleLongRightArrow]y\[DoubleLongRightArrow]....
DoubleRightArrow[x, y, ...] displays as x \[DoubleRightArrow] y \[DoubleRightArrow] ....