GURU GIRARATH KOS is a dictionary of the Guru Granth Sahib compiled by the Nirmala scholar Pandit Tara Singh Narotam. The kos, completed in AD 1889, is in two volumes printed at Rajendra Press, Patiala the first (pp. 702) in 1895 and the second (pp. 706) in 1898. The first volume has a lengthy Introduction which carried no title except the abbreviated form of the mul mantra, i.e. Ik Oankar Satguru Prasad, at the head. The Introduction beginning with a definition of the word kos contains detailed information about the contents of the book, the method of arrangement of words and phrases, abbreviations used, a list of the Sanskrit prefixes, some specimens of the words which have different meanings in Sanskrit and Persian, and a few examples of the words which take different forms in different languages of India.

In accordance with the method employed by some of the lexicographers of ancient and medieval India, vocables have been arranged in the initial letter final consonant order. Unlike some earlier dictionaries, the Guru Girdrath Kos contains all categories of words nouns, adjectives, verbal forms, pronominal forms, adverbs, conjunctions and even some post positions, some of them obscure and obsolete. The work is comprehensive in design. Words and word groups requiring explanation have been included and defined very elaborately in some cases.

Some very simple words and words of everyday use also figure in the Kos. No grammatical information about the individual words has been provided, though the language to which each belongs has been alluded to.A long list of languages has been given while preparing a key to the abbreviations, but decisions about assigning a word to a language are on occasions arbitrary. A word is accepted to be of Sanskrit or Arabic or Persian if it has been used in its tatsama (original) form; otherwise it is pronounced desi (indigenous).

In most cases, the verses of the Guru Granth Sahib containing the words or phrases entered have been quoted. As far as possible all possible meanings or shades of meaning of a word in its use in the Guru Granth Sahib have been provided. Interpretations in some instances are preferred which are not in keeping with any of the connotations of the word phrase as used in the Guru Granth Sahib or which may even be contrary to the principles of the Sikh faith. The language of the Kos is Sadh Bhakha.