  Applying an automatic neighbour search algorithm to the 3D UZC galaxy
catalogue (Falco 1999) we have identified 291 compact groups (CGs) with
redshifts between 1000 and 10000 km/s. The sample is analysed to investigate
whether Triplets display kinematical and morphological characteristics similar
to higher order CGs (Multiplets). It is found that Triplets constitute low
velocity dispersion structures, have a gas-rich galaxy population and are
typically retrieved in sparse environments. Conversely Multiplets show higher
velocity dispersion, include few gas-rich members and are generally embedded
structures. Evidence hence emerges indicating that Triplets and Multiplets,
though sharing a common scale, correspond to different galaxy systems. Triplets
are typically field structures whilst Multiplets are mainly subclumps (either
temporarily projected or collapsing) within larger structures. Simulations show
that selection effects can only partially account for differences, but
significant contamination of Triplets by field galaxy interlopers could
eventually induce the observed dependences on multiplicity.
