combination

n. joining, union (of two or more persons or things); number of things combined; motorcycle with a sidecar

In combinatorial mathematics, a combination is an un-ordered collection of unique elements. (An ordered collection is called a permutation.) Given S, the set of all possible unique elements, a combination is a subset of the elements of S. The order of the elements in a combination is not important (two lists with the same elements in different orders are considered to be the same combination). Also, the elements cannot be repeated in a combination (every element appears uniquely once); this is often referred to as "without replacement/repetition". This is because combinations are defined by the elements contained in them, s the set {1, 1, 1} is the same as {1}. For example, from a 52-card deck any 5 cards can form a valid combination (a hand). The order of the cards doesn't matter and there can be no repetition of cards.
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Noun
1. a collection of things that have been combined; an assemblage of separate parts or qualities
(hypernym) collection, aggregation, accumulation, assemblage
(hyponym) amalgam
(derivation) aggregate, combine
2. a coordinated sequence of chess moves
(hypernym) sequence
3. a sequence of numbers or letters that opens a combination lock; "he forgot the combination to the safe"
(hypernym) sequence
4. a group of people (often temporary) having a common purpose; "they were a winning combination"
(hypernym) unit, social unit
(derivation) combine
5. an alliance of people or corporations or countries for a special purpose (formerly to achieve some antisocial end but now for general political or economic purposes)
(hypernym) alliance, coalition, alignment, alinement
(hyponym) combination in restraint of trade
(derivation) combine
(classification) politics, political science, government
6. the act of arranging elements into specified groups without regard to order
(hypernym) mathematical process, mathematical operation, operation
(derivation) aggregate, combine
7. the act of combining things to form a new whole
(synonym) combining, compounding
(hypernym) change of integrity
(hyponym) attachment, affixation

n. concoction

(n.)
The result of combining or uniting; union of persons or things; esp. a union or alliance of persons or states to effect some purpose; -- usually in a bad sense.
  

(n.)
The different arrangements of a number of objects, as letters, into groups.
  

(n.)
The act or process of uniting by chemical affinity, by which substances unite with each other in definite proportions by weight to form distinct compounds.
  

(n.)
The act or process of combining or uniting persons and things.