What does fortyfold mean?
Fortyfold denotes a quantity or degree that is exactly forty times as large as some starting point. It belongs to the family of '-fold' words — twofold, tenfold, hundredfold — which English uses to express multiplication compactly and vividly. The word operates in two ways: as an adjective, as in 'a fortyfold increase in wheat yields', and adverbially, as in 'the population grew fortyfold within a century'. It appears most often in formal, scientific, economic, agricultural, and religious writing, where dramatic proportional change needs precise expression; biblical texts famously employ it to describe abundant reward. Its connotations are generally striking and positive, since a fortyfold change implies extraordinary growth rather than modest variation. Though uncommon in everyday speech, fortyfold offers writers a concise, authoritative alternative to phrases like 'multiplied by forty', lending statistical claims both clarity and rhetorical force.
Equal to or consisting of forty times the original quantity, size, or degree.
"The plot yielded a fortyfold harvest after the new irrigation system was installed."
Typically used attributively before a noun such as 'increase', 'return', or 'growth'.
To an extent or degree forty times greater than the initial measure.
"Farmland values in the region rose fortyfold during the boom."
Used predicatively with verbs such as 'grow', 'increase', or 'multiply'.
"Fortyfold" descends from the Old English '-feald' suffix — the same ancient root that gave us "manifold" — making it a living relic of a thousand-year-old way of counting.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fortyfold
Fortyfold derives from Old English, combining the number 'forty' (from the Germanic root underlying 'four') with the ancient suffix '-feald', meaning 'times or folds of'. The '-fold' suffix traces back through Old English 'feald' to Proto-Germanic origins shared with other Germanic languages, and it survives today in words such as 'twofold', 'tenfold', and 'manifold'. Words like 'fourteen' and 'fortnight' descend from the same Germanic numerical root.
How fortyfold is actually used
Fortyfold is rare outside formal, statistical, agricultural, or biblical contexts, where multiplicative language ('-fold' words) remains conventional. It carries a neutral-to-positive connotation, usually signalling dramatic growth. It functions attributively (a fortyfold increase) or predicatively (to grow fortyfold).
Easily confused with fortyfold
A fortnight is a period of two weeks, whereas fortyfold is a multiplier of forty.