One of the methods for extracting information from a data set is clustering the data set according to some rule. In this paper, datasets are represented as finite metric spaces. A finite metric space is a pair (X, d X ), where X is a finite set and d X : X × X → R + is a distance function. We denote by M the collection of all finite metric spaces.We start by providing a definition of a clustering method with some examples. For any n ∈ N, we denote the set {1, 2, . . . , n} by [1 : n]. Given (X, d X ) ∈ M, we denote by P (X), the collection of all partitions of X. Precisely, every P ∈ P (X) is a family of setsas a block of P . We denote by P, the collection of all pairs (X, P X ), where X ∈ M and P X ∈ P (X). Formally,Example 2.2 An example of a clustering method is the discrete clustering that partitions every metric space into singletons. Precisely, we have C disc : M → P with C disc ((X, d X )) = (X, S X ), where S X ∈ P (X) is the partition of X into singletons.Example 2.3 Another example of a clustering method is the full clustering that partitions every metric space into a single block. Precisely, we have C full : M → P with C full ((X, d X )) = (X, {X}).There are various other examples of clustering methods such as partitioning into clusters whose diameter is bounded above by a constant, or partitioning into clusters whose diameter is bounded below by a constant, and so on [JS72]. Since we are working with finite metric spaces, the metric structure is the only information we have for determining a partition. Thus, 3 it seems natural that for (X, d X ), (Y, d Y ) ∈ M and a structure preserving map f : X → Y , a partition of Y induced by a clustering method C can be determined, at least partially, using the map f and a partition of X induced by the same clustering method C. Precisely, we want a clustering method C to be a functor, see [CM13].In order to view a clustering method C as a functor, we need to view M and P as categories. We refer the readers to [Jac12, Spi14] for an account on category theory. We define the categorical structure on M and P as follows:Definition 2.4 (Category of Finite Metric Spaces). Let M, by abuse of notation, denote the category of finite metric spaces. The objects of M are finite metric spaces (X, d X