Order is applicable to elementary as well as complex reaction whereas molecularity is applicable only for elementary reaction." For complex reaction molecularity has no meaning" Explain

  The number of reacting species (atoms ,molecules or ions) which collide simultaneously to bring about a chemical reaction is called molecularity of a reaction.\

Complex reaction takes place in a number of  elementary steps.Complex reaction doesnot  proceed by simultaneous collision of all  the particles  involved  in the reaction. therefore  for complex reaction  molecularity has no meaning