A geodesic metric space is a metric space in which any two points are joined by a path isometric
to the real interval
(Bridson and Haefliger 1999,
p. 4). Such a path realizes the distance
between its endpoints. This condition requires a globally
distance-minimizing path, beyond
local minimization along a curve.
For example, Euclidean space and a connected graph with each edge realized as an interval of length 1, equipped with the path metric, are geodesic metric spaces. The comparison condition for a CAT(0) space further controls distances between points on these paths.