We have introduced here a new type of corpus annotation which we call Etymological Annotation (EA). We propose this new type because although, over the years, scientists have proposed corpus annotation of various types (Atkins, Clear and Ostler 1992, Biber 1993, Leech 2005), nobody has ever suggested that words included within corpora need to be annotated at their etymological level so that one can retrieve necessary linguistic information relating to antiquity of words and terms used in corpora. The applicational relevance of etymologically annotated corpora may be visualized in language description, language planning, language education, lexicology, language technology as well as in compilation of general, historical, learner and special dictionaries. In case of those languages, where one comes across large number of words borrowed from neighbouring and foreign languages, the proper identification of source of origin of words carries tremendous referential relevance in cross-lingual lexical database generation, morphological processing, part-of-speech tagging, e-learning, digital lexical profile generation, information retrieval, machine learning, and language documentation. Thus, etymologically annotated corpora become an essential resource of applied linguistics and language technology. We propose here to define this new event with necessary direction and guidance to develop etymologically tagged language corpora for all natural languages.