JUDGMENT : S.D. Shah, J. On being required to make a reference under section 256(2) of the Income-tax Act, 1961, the Income-tax Tribunal has referred the following question for our opinion : "Whether the books valued at Rs. 5,324, the cost of which is allowed as revenue expenditure, are 'plant' and entitled to the allowance of development rebate ? " 2. In order to answer the aforesaid question, it would be necessary to set out the relevant facts herein : (i) The relevant assessment year is 1970-71. The assessee claimed development rebate on three items, one of them being "books" of the value of Rs. 5,324. The Income-tax Officer found that the books were not covered by machinery or plant directly and wholly used for the purpose of business. However, the cost thereof was allowed as revenue expenditure but the claim for development rebate was rejected. (ii) On being aggrieved thereby, the assessee preferred an appeal to the Appellate Assistant Commissioner who found that "books" would fall within the meaning of the word "plant" under section 43(3) of the said Act, and, therefore, development rebate was admissible. He, therefore, directed the Income-tax Officer to allow development rebate to the assessee on the books at the appropriate rate. (iii) Being aggrieved by the said order passed by the Appellate Assistant Commissioner, the Revenue went in appeal and the Income-tax Appellate Tribunal confirmed the view taken by the Appellate Assistant Commissioner holding that the "books" are "plant" within the meaning of section 32 of the Income-tax Act, 1961, and, therefore, the assessee was entitled to development rebate. 3. Under section 32 of the Income-tax Act, 1961, in respect of depreciation on buildings, machinery, plant or furniture owned by the assessee and used for the purpose of business or profession, the deductions stipulated therein are allowed subject to the provisions of section 34. 4. Section 43 defines certain terms relevant to income from profits and gains of business or profession accruing under sections 28 to 41. Section 43(3) defines "plant" to include ships, vehicles, books, scientific apparatus and surgical equipment used for the purposes of the business or profession. It is thus clear that for the purpose of section 32, the word "plant" would include books and the assessee would be entitled to depreciation under section 32 if the said conditions of section 32 are satisfied. 5. It is thus clear that for the purpose of section 32, the word "plant" would include books and the assessee would be entitled to depreciation under section 32 if the said conditions of section 32 are satisfied. 5. The question whether the books would be included within the meaning of the word "plant" for the purpose of entitlement of the assessee to depreciation or for development rebate is no longer res integra. In the case of CIT v. Elecon Engineering Co. Ltd. 1974 (96) ITR 672, a Division Bench of this court, speaking through justice P.D. Desai (as he then was), has taken the view that the word "plant" in its ordinary meaning is a word of wide import and it must be broadly construed having regard to the fact that articles like books and surgical instruments are expressly included in the definition of plant under section 43(3) of the Act. The relevant test to be applied is does it fulfil the function of plant in the assessee's trading activity? Is it the tool of the taxpayer's trade? If it is, then it is plant, no matter that it is not very long-lasting or does not contain working parts such as a machine does and plays merely a passive role in the accomplishment of trading purposes. On the question as to whether the drawings and apparatus were "books" and, therefore, they were "plant" within the enlarged meaning of the said word as given under section 43(3) of the Act, the Division Bench observed as under ( at page 681 ) : "We will first consider the question whether drawings and patterns acquired by the assessee are 'books', for the inclusive definition of the word 'plant' in section 43(3) of the Act expressly declares that 'books' used for the purposes of the business or profession of the assessee, that is, used for the purpose of enabling the assessee to carry on his business or profession and earn income therefrom, are 'plant' within the meaning of section 32. Now, the word 'book' has not been defined in the Act and it is not a term of art. It is an ordinary English word of everyday use and it must, therefore, be assigned its natural meaning as understood in common parlance subject, of course, to the context in which it is used here. Now, the word 'book' has not been defined in the Act and it is not a term of art. It is an ordinary English word of everyday use and it must, therefore, be assigned its natural meaning as understood in common parlance subject, of course, to the context in which it is used here. In popular sense, book means a collection of a number of leaves or sheets of paper or of other substance, blank, written or printed, of any size, shape and value, held together along one of the edges so as to form a material whole and protected on the front and back with cover of more or less durable material. That this is how the word 'book' is understood in ordinary usage is evident from the third meaning of the word given in the Shorter Oxford English Dictionary, third edition, page 202 : 'gen. A collection of sheets of paper or other substance, blank, written or printed, fastened together so as to form a material whole ; esp. such a collection fastened together at the back, and protected by covers ; also, a literary composition long enough to make one volume, as dist. from a tract, pamphlet, essay, etc.' 6. In this rather wide sense not only a literary or scientific book, book of art, law book, religious book, text book, dictionary and so on but also an account book, minutes book, cheque book, pocket diary, notebook and a hundred other varieties of objects satisfying the above description would be books. For the purpose of ascertaining the true meaning of the word 'books' in section 43(3) in which it occurs in conjunction with the expression 'used for the purposes of the business or profession', however, one must have regard not only to the physical but also to the functional characteristics of a 'book'. A book within the meaning of section 43(3) must in addition to conforming to its physical form denoted by the above definition, be functionally useful for the purpose of the assessee's business or profession. It must be a tool of his trade-an article which is a part of the apparatus with which his business or profession is carried on. It must have the utility value enabling its owner to pursue his business or profession with greater advantage. It must be a tool of his trade-an article which is a part of the apparatus with which his business or profession is carried on. It must have the utility value enabling its owner to pursue his business or profession with greater advantage. In the ultimate analysis, therefore it would appear that a book within the meaning of section 43(3) must be an object or article which must satisfy a dual test ;it must bear both physical and functional characteristics of a book." 7. The aforesaid decision of the Division Bench of this court in the case of Elecon Engg. Co. Ltd. 1974 (96) ITR 672 is approved by the Supreme Court in the case of Scientific Engg. House P. Ltd. v. CIT 1986 (157) ITR 86 . In the aforesaid decision, the Supreme Court held that the drawings, business charts, plants, processing data and other literature comprised in the "documentation service" as specified in clause 3 constituted "book" and fell within the definition of "plant" in section 43(3) of the Income-tax Act, 1961. The court expressly approved the decision of the Division Bench of this court in the case of Elecon Engg. Co. Ltd. 1974 (96) ITR 672. The decision of this court in the case, of Elecon Engg. Co. Ltd. 1974 (96) ITR 672 was also carried in appeal to the Supreme Court and in the case of CIT v. Elecon Engg. Co. Ltd. 1987 (166) ITR 66, the Supreme Court has affirmed the said decision. 8. In view of the aforesaid legal position and in view of the express provision of section 43(3) of the Act which gives an inclusive meaning to the word "plant", we are of the opinion that the Tribunal was right in allowing development rebate to the assessee on books. 9. In the result, we answer the question in the affirmative, i.e., in favour of assessee and against the Revenue. No costs.