A bunch or group of several discrete items that are close to each other. • A group of galaxies, nebulae, or stars that appear to the naked eye to be near each other. • An ensemble of bound atoms (especially of a metal) or molecules, intermediate in size between a molecule and a bulk solid. • A group of computers that work together. • A logical data storage unit containing one or more physical sectors (see block (noun)). • A group of cases of the same disease occurring around the same place or time. • Synonym of lexical bundle (“a sequence of two or more words that occur in a language with high frequency but are not idiomatic”). • A set of bombs or mines released as part of the same blast. • In full oak leaf cluster: a small bronze or silver device shaped like a twig of oak leaves and acorns which is worn on a ribbon to indicate that the wearer has been conferred the same award or decoration before; an oakleaf. • A secundal chord of three or more notes. • A pronounceable group of consonants that occur together: a consonant cluster. • In cluster analysis: a subset of a population whose members are similar enough to each other and distinct from others as to be considered a separate group; also, such a grouping in a set of observed data that is statistically significant. • A number of individuals (animals or people) collected in one place or grouped together; a crowd, a mob, a swarm. • Euphemistic form of clusterfuck (“a chaotic situation where everything seems to go wrong”).