Irreversible binomial

They also belong to the same part of speech: nouns (milk and honey), adjectives (short and sweet), or verbs (do or die).

[1] 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".

Idioms like rock and roll, the birds and the bees, and collocations like mix and match, and wear and tear have particular meanings apart from or beyond those of their constituent words.

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.

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 so (like between a rock and a hard place, five and dime).

Somewhat in between are more subtle figures of speech, synecdoches, metaphors, or hyperboles (like cat and mouse, sick and tired, barefoot and pregnant).

In law and official documents, there are many irreversible binomials and triplets consisting of near synonyms, such as the oft-heard terms and conditions[6] and cease and desist.