SystemsModelLabels is an option to StateSpaceModel and TransferFunctionModel that specifies labels of the variables.
SystemsModelOrder[ss] gives the order of the StateSpaceModel object ss.
TotalWidth is an option which can be set for output streams to specify the maximum total number of characters of text that should be printed for each output expression. Short ...
Uncompress["string"] recovers an expression from a compressed string representation generated by Compress.Uncompress["string", h] wraps the head h around the expression ...
VertexComponent[g, {v_1, v_2, ...}] gives the vertices in the graph g that have a path to at least one of v_1, v_2, ....VertexComponent[g, {v_1, v_2, ...}, k] gives the ...
$FrontEnd is a global variable that specifies to what front end object, if any, the kernel is currently connected.
$Messages gives the list of files and pipes to which message output is sent.
$NumberMarks gives the default value for the option NumberMarks, which specifies whether ` marks should be included in the input form representations of approximate numbers.
Introduction to Dynamic Advanced Dynamic Functionality
SQLServer[...] is an object that represents a server process started in Mathematica.