Definition: a word; a unit forming a part of a sentence; a unit made up of a letter or of letters, possessed of sense; cf. अक्षरसमुदायः पदम् । अक्षरं वा । V.Pr. VIII. 46, 47. The word originally was applied to the individual words which constituted the Vedic Samhitā; cf. पदप्रकृतिः संहिता Nir.I.17. Accordingly, it is defined in the Vājasaneyi Prātiśākhya as ' अर्थः पदम् ' (V. Pr. III. 2) as contrasted with ' वर्णानामेकप्राणयोगः संहिता ' (V.Pr.I.158). The definition ' अर्थः पदम् ' is attributed to the ancient grammarian 'Indra', who is believed to have been the first Grammarian of India. Pāņini has defined the term पद as ' सुप्तिङन्तं पदम् ' P.I.4.14. His definition is applicable to complete noun-forms and verb-forms and also to prefixes and indeclinables where a case-affix is placed and elided according to him; cf. अव्ययादाप्सुपः P. II. 4. 82. The noun-bases before case affixes and tad. affixes, mentioned in rules upto the end of the fifth adhyāya, which begin with a consonant excepting य् are also termed पद by Pāņini to include parts of words before the case affixes भ्याम्, भिस्, सु etc. as also before the tad. affixes मत्, वत् etc. which are given as separate padas many times in the pada-pātha of the Vedas; cf. स्वादिष्वसर्वनामस्थाने P. I. 4. 17. See for details the word पदपाठ. There are given four kinds of padas or words viz. नाम, अाख्यात, उपसर्ग and निपात in the Nirukta and Prātiśākhya works; cf. also पदमर्थे प्रयुज्यते, विभक्त्यन्तं च पदम् M. Bh. on P. I. 2. 64 Vārt. 19, वर्णसमुदायः पदम् M.Bh. on I.1.21 Vārt. 5, पूर्वपरयोरर्थोपलब्धौ पदम् Kāt. I.1.20, पदशब्देनार्थ उच्यते Kaiyata on P.I.2.42 Vārt. 2; cf. also पद्यते गम्यते अर्थः अनेनेति पदमित्यन्वर्थसंज्ञा Nyāsa on P.III. 1.92. The verb endings or affixs ति, तस् and others are also called पद. The word पद in this sense is never used alone, but with the word परस्मै or अात्मने preceding it. The term परस्मैपद stands for the nine affixes तिप्, तस्, ...मस्,while the term आत्मनेपद stands for the nine affixes त, आताम् ... महिङ्. cf. ल: परमैपदम्, तङानावात्मनेपदम्. It is possible to say that in the terms परस्मैपद and अात्मनेपद also, the term पद could be taken to mean a word, and it is very likely that the words परस्मैपद and अात्मनेपद were originally used in the sense of 'words referring to something meant for another' and 'referring to something meant for self' respectively. Such words, of course, referred to verbal forms, roughly corresponding to the verbs in the active voice and verbs in the passive voice. There are some modern scholars of grammar, especially linguists, who like to translate परस्मैपद as 'active voice' and आत्मनेपद as ' passive voice'. Pāņini appears, however, to have adapted the sense of the terms परस्मैपद and आत्मनेपद and taken them to mean mere affixes just as he has done in the case of the terms कृत् and तद्धित. Presumably in ancient times, words current in use were grouped into four classes by the authors of the Nirukta works, viz. (a) कृत् (words derived from roots)such as कर्ता, कारकः, भवनम् etc., (b) तद्धित (words derived from nouns) such as गार्ग्यः, काषायम्, etc., (c) Parasmaipada words viz. verbs such as भवति, पचति, and (d) Ātmanepada words i.e. verbs like एधते, वर्धते, etc.Verbs करोति and कुरुते or हरति and हरते were looked upon as both परस्मैपद words and आत्मनेपद words. The question of simple words, as they are called by the followers of Pāņini, such as नर, तद्, गो, अश्व, and a number of similar underived words, did not occur to the authors of the Nirukta as they believed that every noun was derivable, and hence could be included in the kŗt words.