crucial

Etymology

1706, from French crucial, a medical term for ligaments of the knee (which cross each other), from Latin crux, crucis (“cross”) (English crux), from the Proto-Indo-European *(s)ker- (“to turn, to bend”). The meaning “decisive, critical” is extended from a logical term, Instantias Crucis, adopted by Francis Bacon in his influential Novum Organum (1620); the notion is of cross fingerboard signposts at forking roads, thus a requirement to choose.

adj

1. Essential or decisive for determining the outcome or future of something; extremely important; vital.
   The battle of Tali-Ihantala in 1944 is one of the crucial moments in the history of Finland.
   A secure supply of crude oil is crucial for any modern nation, let alone a superpower.
   The perfume industry is facing a major problem: maintaining constant levels of quality is crucial, but it is increasingly difficult to obtain a regular supply of all the necessary natural ingredients. 2014-03-07, Nicole Vulser, “Perfume manufacturers must cope with the scarcity of precious supplies”, in The Guardian Weekly, volume 190, number 13, page 30
   Vocabulary provides a foundation from which grammar, phonology, and morphology emerge, and in a subject area it provides access to conceptual knowledge. Vocabulary selection for pedagogical purposes is therefore crucial. 2018, Clarence Green, James Lambert, “Advancing disciplinary literacy through English for academic purposes: Discipline-specific wordlists, collocations and word families for eight secondary subjects”, in Journal of English for Academic Purposes, volume 35, →DOI, page 106
   Language is crucial because it is the best weapon against violence. When children don’t have the words to express their thoughts, they raise their fists. October 1, 2021, A Falun Dafa practitioner in France, “Using Truthfulness-Compassion-Forbearance to Guide My Young Students”, in Minghui
2. (archaic) Cruciform or cruciate; cross-shaped.
3. (slang, especially Jamaica, Bermuda) Very good; excellent; particularly applied to reggae music.
   Delbert Wilkins is the most crucial pirate radio DJ in Brixton.