decadeslong

Decadeslong is a compound adjective used to describe something that lasts for many decades or spans multiple decades. It is commonly applied to events, processes, or trends that endure over a long historical period, often implying long-term consequences or a sustained period of activity. Examples include a decades-long conflict or a decades-long renovation project.

Spelling and usage notes emphasize hyphenation in formal writing. The standard form in many style guides is decades-long when the adjective directly precedes a noun (as in “a decades-long conflict”). Some writers also use the variant decadeslong, especially in informal contexts, though this form is less widely accepted in formal prose. When used after a linking verb, such as in “the conflict has been decades long,” some editors prefer decades-long or may allow decades long depending on house style. In general, decades-long is the recommended form for attributive use before a noun, while the two-word decades long is less common and can appear in less formal contexts.

Etymology and usage context: decadeslong derives from decade, a ten-year period, combined with long to convey an extended duration. It overlaps with similar expressions like multi-decade or long-running, but decades-long specifically signals a span of multiple decades rather than a shorter or indefinite period. It is frequently employed in journalism, history, policy analysis, and scholarly writing to frame long-term timelines, legacies, or persistent conditions. While widely understood, its preferred spellings vary by style guide, with decades-long being the most common in formal English.