Title: Multiple stars: designations, catalogs, statistics

Author: A. Tokovinin

An account of the IAU meetings on the designation of multiple-star
components is given, with some firm recommendations and a conclusion
that not only components, but systems, centers-of-mass, and hierarchy
needs consistent designations. A short review of scarce available
results on multiple-star statistics follows: the frewuency of
different multiplicities in the field, periods of spectroscopic
sub-systems, relative orbit orientation, empirical stability limit,
and period-period diagram with its possible connection to formation of
multiple stars.