Uninstall[link] terminates an external program started by Install, and removes Mathematica definitions set up by it.
Update
(Built-in Mathematica Symbol) Update[symbol] tells Mathematica that hidden changes have been made which could affect values associated with a symbol. Update[] specifies that the value of any symbol could ...
UpValues[f] gives a list of transformation rules corresponding to all upvalues defined for the symbol f.
ValueQ
(Built-in Mathematica Symbol) ValueQ[expr] gives True if a value has been defined for expr, and gives False otherwise.
VectorPoints is an option to VectorPlot, ListVectorPlot, and related functions that determines how many field vectors to draw.
VertexInDegree[g] gives the list of vertex in-degrees for all vertices in the graph g.VertexInDegree[g, v] gives the vertex in-degree for the vertex v.
VertexRenderingFunction is an option for GraphPlot and related functions that gives a function to generate the graphics primitives to use in rendering each vertex.
WakebyDistribution[\[Alpha], \[Beta], \[Gamma], \[Delta], \[Mu]] represents Wakeby distribution with shape parameters \[Beta] and \[Delta], scale parameters \[Alpha] and ...
WindowSize is a notebook option that specifies the size of window that should be used to display a notebook on the screen.
WindowTitle is an option that specifies the title to give for a window.