  We present a study focusing on the nature of compact groups through the study
of their elliptical galaxies. We determine velocity dispersions ($\sigma$) for
18 18 bright elliptical galaxies located in the core of Hickson compact groups
and a control sample of 12 bright bona fide ellipticals located in the field or
very loose groups. Several tests are carried out to avoid sources of systematic
effects in $\sigma$ measurements. We use these velocity dispersions to compare
the position of 11 compact group galaxies in the Fundamental Plane to that of a
large and homogeneous sample of elliptical galaxies (Burstein et al. 1987). We
find that little or no significant difference exists, as far as the Fundamental
Plane is concerned, between ellipticals in compact groups and their
counterparts in other environments.
