It may refer to:
- - a group of people having a common purpose or interest; a society or club
- - the act of associating or the state of being associated
- - friendship or companionship: their association will not last.
- - a mental connection of ideas, feelings, or sensations: association of revolution with bloodshed.
- - (Psychology) psychol the mental process of linking ideas so that the recurrence of one idea automatically recalls the other. See also free association
- - (Chemistry) chem the formation of groups of molecules and ions, esp in liquids, held together by weak chemical bonds
- - (Environmental Science) ecology a group of similar plants that grow in a uniform environment and contain one or more dominant species
- - The act of associating or the state of being associated.
- - An organized body of people who have an interest, activity, or purpose in common; a society.
- - A mental connection or relation between thoughts, feelings, ideas, or sensations. A remembered or imagined feeling, emotion, idea, or sensation linked to a person, object, or idea.
- - A correlation or causal connection: the association of exercise with improved sleep.
- - Chemistry Any of various processes of combination, such as hydration, solvation, or complex-ion formation, depending on relatively weak chemical bonding.
- - Ecology A large number of organisms in a specific geographic area constituting a community with one or two dominant species.