Abstract
The third edition of the International Vocabulary of Metrology (VIM) has introduced the concept of kind of quantity as the 'aspect common to mutually comparable quantities'. While the concept is a fundamental one, as it is relevantly used in several definitions throughout VIM, its definition is critical for several reasons. Not only is the division of the concept of 'quantity' according to 'kind of quantity' to some extent arbitrary, as noted in the Vocabulary, but also the distinction between the concepts of 'quantity' and 'kind of quantity' is to some extent arbitrary. This article discusses this subject and suggests a possible solution to some of the issues identified.