Merism
A figure that names the extremes of something to imply the whole — 'heaven and earth', 'young and old'.
A merism, from the Greek 'merismos' ('division'), is a figure in which a totality is expressed by naming two or more of its parts, typically its opposite ends. 'Heaven and earth' means the entire created order; 'young and old' means everyone; 'body and soul' means the whole person. The parts are chosen precisely because their range implies everything between them.
Merism is a favourite device of the Hebrew Bible, where much of the world is described through paired extremes ('the heavens and the earth', 'day and night', 'flesh and spirit'). It shows up in legal drafting ('all matters, whether now known or unknown') for the same reason — the paired extremes are meant to leave no interpretive gap.
The figure is close to synecdoche, but distinct: synecdoche uses a part for the whole (a 'hand' for a worker); merism uses paired parts specifically because their range is meant to encompass everything between them. Editors sometimes fold the two together; the distinction is worth keeping because it names what merism does that synecdoche does not.
Common mistake: reading a merism literally. 'They searched high and low' does not describe a two-storey search; it means they searched everywhere. Insisting on the literal reading of a merism strips the figure of its meaning and produces the sort of pedantry that comedy writers thrive on.
“In the beginning God created the heavens and the earth.”
Keep reading the glossary
A figure where the part stands for the whole, or the whole for the part.
Calling something by the name of an associated thing — 'the crown' for 'the monarchy'.
A rhetorical figure that expresses one idea by joining two nouns with 'and' where a noun and modifier would suffice.
A rhetorical scheme in which successive clauses have the same length and grammatical structure.