define macroname numarg
      statement
      ...
end

Define a macro named macroname with numarg arguments containing statement ... Within the definition, the arguments are referenced as $1, $2, up to $numarg and may contain any statement except define. Macros may call other macros and itself. Macro definition using a ysh command name will be lost, i.e., although you can define them they are not accessible.

macroname $1 ...

Invoke the previously defined macro named macroname with the arguments $1 .... The right number of arguments must be supplied and they must be of the correct types.