Last rites (plural) is a popular term given to the sacraments (plural) given to someone in danger of death. Last rites includes confession, anointing of the sick, and a final reception of the Eucharist (called viaticum, which is Latin for “traveling provisions”).
Extreme unction (Latin, “final anointing”) is an older name for the sacrament known more commonly today as the anointing of the sick. The name was modified in order to highlight that the sacrament can be given to any Catholic who is seriously ill, with a view to preparing them for death if need be.