  Gamma-ray bursts can be divided into three groups ("short", "intermediate",
"long") with respect to their durations. This classification is somewhat
imprecise, since the subgroup of intermediate duration has an admixture of both
short and long bursts. In this paper a physically more reasonable definition of
the intermediate group is presented, using also the hardnesses of the bursts.
It is shown again that the existence of the three groups is real, no further
groups are needed. The intermediate group is the softest one. From this new
definition it follows that 11% of all bursts belong to this group. An
anticorrelation between the hardness and the duration is found for this
subclass in contrast to the short and long groups. Despite this difference it
is not clear yet whether this group represents a physically different
phenomenon.
