I studied that RBCs, WBCs & platelets are called corpuscles because these cells don't divide but the fact is that even neurons & other differentiated cells too don't divide.I agree on the point that the corpuscles are much more specialized than the others but I still want to know the actual reason of such nomenclature & moreover why now we use the terms erythrocytes,leucocytes & thrombocytes for RBCs,WBCs & platelets?

Corpuscle is an archaic term that includes all of the cells occurring in blood. From your question you already know how inadequate the term has become. Continuing on this theme the definition also fails because WBCs do divide. So, the term isn’t a useful way to classify blood cells. The RBCs, WBCs & platelets nomenclature reflects how to tell the cells apart under a microscope.


why now we use the terms erythrocytes,leucocytes & thrombocytes for RBCs,WBCs & platelets?
Latin was the language of medicine & science. The names are synonyms reflecting the English and Latin “versions” of the name (erythro = red)

Corpuscles are same as cells, and according to my knowledge it has nothing to do with its division or else.

Corpuscle is an archaic term that has several meanings:

A small free floating biological cell, especially ones occurring in blood
A nerve ending such as Meissner's corpuscle or a Pacinian corpuscle
A subatomic particle obsoleted by the modern electron and used in J.J. Thomson's plum-pudding model of the atom
A single, infinitesimally small, particle of light. Isaac Newton proposed this term to represent a concept that was quite different from the idea of a photon.
A member of Corpus Christi College, Oxford, or of Corpus Christi College, Cambridge.
Term referring to an employee of the United States Army Corps of Engineers


with courtesy of wikipedia.org