A collective noun is a word used to define a grouping of people, animals, objects or concepts. Many of the nouns used are colourful, or even fanciful; this originated in an English hunting tradition (of uncertain origin) for giving poetic names to prey. (The phrase "terms of venery" is an archaic synonym for collective nouns - "venery" in this context meaning the "act of hunting").
While this tradition dates back to at least the 15th century, interest in collective nouns has always remained high, and the creation of candidate collective nouns has been a pastime of many writers ever since. Some have achieved "legitimacy" (here defined as having an entry in a respected dictionary), others have not.
Several collective nouns perform double, triple or even more duties. "Herd" is a legitimate collective noun for dozens of animals and (rather curiously) the mythical fairy. (Also interestingly, "herd" can be used with wild horses and domestic cows, but not with domestic horses). Likewise, "flock" is a generic collective noun for all sorts of flying birds. The all-time champion collective noun is "set", for it can legitimately be used as a collective noun for a vast number of concepts (a set of ideals, plans, ambitions, principles, objectives, etc) or inanimate (typically manufactured) objects (knives, spoons, keys, dinnerware, manuals, etc).
In addition to subject-specific collective nouns, there are a number of collective nouns that deal wth specific quantities: eg. a pair (2), a trio (3), a dozen (12), a "baker's dozen" (13), a score (20), a gross (144). Other terms such as "quartet" (4), "quintet" (5), etc, are generally only used when referring to people, typically performers.
The collective nouns here generally can be used to describe any sized group of the relevant subject. Occasionally they can only be used to describe the subject performing a specific action; eg. a "paddling of ducks" only refers to duck on water. Certain nouns have been excluded from this list because the collective noun is too highly specific and/or could be used to describe a single subject. A single cow can "stampede" (an unusual, but legitimate usage) and a single committee member can conceivably constitute a "quorum".
All of the collective nouns presented have been verified in one or more dictionaries, except where noted as "spurious" or "uncertain". English usage is, of course, in a constant state of evolution, hence the denotation of "uncertain" should not be taken to mean that the noun is categorically wrong, but only that no verification has been found (as yet) in a dictionary. Some nouns have been circulated on websites for humourous reasons, these are noted as "spurious". In at least two cases (an "abomination of monks" and "a court of kangaroos") some authoritative resources allege them to be accurate, however research has proved these to be spurious as well. Other misinterpretations are included as well; some on-line resources give "rookery" as a collective noun for seals, penguins or herons, however this is incorrect. The term only refers to the breeding territory itself, and not to the collection of animals.
A significant number of collective nouns involve what must be considered "non-standard" usage of certain words. Some of the examples given for birds are quite fanciful; eg. "A murder of crows", "an exaltation of larks". Nearly everyone would be familiar with the term "library" as it pertains to books, but few would expect to see it as a collective term for any set of books, anywhere (most would assume it to mean a building or room containing books). However this usage (admittedly obscure) is legitimate and is thus included.
Needless to say, many of these nouns are archaic - a "harass of horses" dates to the 1400s, and doesn't appear to have been used much since then. Several of the collective nouns presented are specifically regional (it is unlikely that a "disworship of Scots" was used in Scotland with any frequency). Some alternates can be clearly traced to the evolution of pronunciation in different areas (hence a "parcel of hogs" and a "passel of hogs"). Certain examples defy logic; ferrets are known to be fiercely solitary animals, yet two collective nouns are known to exist ("business" and the old Saxon "fesnying"). This article does not attempt to provide etymologies; these can be found in a dictionary of etymology.
Collective nouns sorted by subject
Collective nouns sorted by collective term
Collective nouns for people
Collective nouns for mammals, non-human
Collective nouns for birds
Collective nouns for reptiles and amphibians
Collective nouns for fish, invertebrates and plants
Collective nouns for objects and concepts