  Let $G$ be a connected reductive group over a non-Archimedean local field. We
prove that its parahoric subgroups are definable in the Denef-Pas language,
which is a first-order language of logic used in the theory of motivic
integration developed by Cluckers and Loeser. The main technical result is the
definability of the connected component of the N\'eron model of a tamely
ramified algebraic torus. As a corollary, we prove that the canonical Haar
measure on $G$, which assigns volume $1$ to the particular \emph{canonical}
maximal parahoric defined by Gross, is motivic. This result resolves a
technical difficulty that arose in Cluckers-Gordon-Halupczok and Shin-Templier
and permits a simplification of some of the proofs in those articles. It also
allows us to show that formal degree of a compactly induced representation is a
motivic function of the parameters defining the representation.
