noun

• A set of items or amount of material procured, gathered or presented together.
• (music) A set of pitch classes used by a composer.
• The activity of collecting.
• (set theory, topology, mathematical analysis) A set of sets; used because such a thing is in general too large to comply with the formal definition of a set.
• A gathering of money for charitable or other purposes, as by passing a contribution box for donations.
• (law) Debt collection.
• (obsolete) The act of inferring or concluding from premises or observed facts; also, that which is inferred.
• (UK) The jurisdiction of a collector of excise.
• (Oxford University, usually in the plural) A set of college exams generally taken at the start of the term.
• The quality of being collected; calm composure.