Irreversible binomial

In linguistics and stylistics, an irreversible binomial,[1] (frozen) binomial,[1] binomial pair, binomial expression, (binomial) freeze, or nonreversible word pair[2] is a pair or group of words used together in fixed order as an idiomatic expression or collocation. The words belong to the same part of speech, have some semantic relationship, and are usually connected by the words and or or.

The expression "macaroni and cheese" is an irreversible binomial. The order of the two keywords of this familiar expression cannot be reversed idiomatically.

The term "irreversible binomial" was introduced by Yakov Malkiel in 1954, though various aspects of the phenomenon had been discussed since at least 1903 under different names: a "terminological imbroglio".[3] Ernest Gowers used the name Siamese twins (i.e., conjoined twins) in the 1965 edition of Fowler's Modern English Usage. The 2015 edition reverts to the scholarly name, "irreversible binomials", as "Siamese twins" had become offensive to some.[4]

Many irreversible binomials are catchy due to alliteration or rhyming, and many have become ubiquitous clichés or catchphrases. Phrases like rock and roll, the birds and the bees, mix and match, and wear and tear have meanings beyond those of the constituent words and are thus inseparable and permanent parts of the English lexicon; the former two are idioms, whilst the latter two are collocations. Ubiquitous collocations like loud and clear and life or death are fixed expressions, making them a standard part of the vocabulary of native English speakers.

The order of elements cannot be reversed.[1]

They may be composed of various parts of speech: milk and honey (two nouns), short and sweet (two adjectives), and do or die (two verbs).

Some English words have become obsolete in general but are still found in an irreversible binomial. For example, spick in spick and span is a fossil word that never appears outside the phrase.[5] Some other words, like vim in vim and vigor or abet in aid and abet, have become rare and archaic outside the collocation. And it's unlikely that many know how to define the word kith in kith and kin, as its meaning has long been tied to the binomial as a fossil word.

Some irreversible binomials are used in legalese. Due to the use of precedent in common law, many lawyers use the same collocations found in documents centuries old, many of which are legal doublets of two synonyms, often one of Old English origin, the other of Latin origin: deposes and says, heirs and successors.

While many irreversible binomials are literal expressions (like washer and dryer, rest and relaxation, rich and famous, savings and loan), some are entirely figurative (like come hell or high water, nip and tuck, surf and turf) or mostly figurative (like between a rock and a hard place, five and dime). Others are somewhat in between these extremes because they are more subtle figures of speech, synecdoches, metaphors, or hyperboles (like cat and mouse, sick and tired, barefoot and pregnant, rags to riches). The terms are often the targets of eggcorns, malapropisms, mondegreens, and folk etymology.

Some irreversible binomials have variations: time and time again is frequently shortened to time and again; a person who is covered in tar and feathers (noun) usually gets that way by the action of a mob that tars and feathers (verb) undesirable people.

The precise wording may change the meaning. A give and take is mutual flexibility, while give or take is a numerical approximation. A person can do something whether it is right or wrong in contrast to knowing the difference between right and wrong; each word pair has a subtly differing meaning. And while five and dime is a noun phrase for a low-priced variety store, nickel and dime is a verb phrase for penny-pinching.