  In this paper, we introduce and study a new distance parameter {\it
triameter} of a connected graph $G$, which is defined as
$max\{d(u,v)+d(v,w)+d(u,w): u,v,w \in V\}$ and is denoted by $tr(G)$. We find
various upper and lower bounds on $tr(G)$ in terms of order, girth, domination
parameters etc., and characterize the graphs attaining those bounds. In the
process, we provide some lower bounds of (connected, total) domination numbers
of a connected graph in terms of its triameter. The lower bound on total
domination number was proved earlier by Henning and Yeo. We provide a shorter
proof of that. Moreover, we prove Nordhaus-Gaddum type bounds on $tr(G)$ and
find $tr(G)$ for some specific family of graphs.
