• Alias: pd. • Prefix operator with built-in evaluation rules. • is by default interpreted as D[y,x]. • is used in mathematics to indicate boundary. • d gives \[Delta], not \[PartialD]. • You can use \[InvisibleComma] in the subscript to to give several variables without having them separated by visible commas. • See also: \[Delta] , \[Del] , \[DifferentialD] , \[Eth] .
\[PartialD]
pd
is used in mathematics to indicate boundary. 
to give several variables without having them separated by visible commas.