Cost accountancy is said to be a science, art and practice of the cost accountant.
Cost accountancy is a science: The term science requires a systematic body of knowledge having certain basic principles and practices which are static in nature. Cost accounting is also governed by number of principles, practices, conventions etc. So cost accounting is said to be a science.
Cost accountancy is an art: The term are requires a systematic knowledge and skill with which a cost accountant discharges his duties and responsibilities.
Cost accountancy is the practice of the cost accountant: Practice includes continuous efforts of a cost accountant in the field of cost accountancy. Without practice a person cannot be a good accountant.