/ˈɪmpækt/
[noun] The strong effect that something has on a person, situation, or object, or the physical force of one thing hitting another. It can describe both a physical collision and a powerful influence.
Before 'impact' meant influence or effect, it literally described something being rammed or packed tightly into something else.
The story of 'impact' begins in Latin, with the verb 'pangere', meaning to fasten, fix, or drive in. When Latin speakers added the prefix 'im-' (a form of 'in-', meaning into or against), they created 'impingere', meaning to push into, strike against, or fasten upon. The past participle of this verb was 'impactus', meaning driven in or pressed together — and it is from this past participle that English borrowed the word directly.
The word entered English in the early 17th century, initially used in medical and scientific contexts to describe things that were physically wedged or pressed together. A tooth that grows at an angle and becomes stuck against another tooth is still called an 'impacted' tooth today, preserving this oldest sense almost perfectly. Early writers used 'impact' mainly as a past participle or adjective, describing objects that had been forcibly pressed into a space.
The noun form — referring to a collision or the force of one object striking another — developed through the 17th and 18th centuries. Writers and scientists used it to describe the moment when two physical objects meet with force: a hammer hitting metal, a cannonball striking a wall, or a comet colliding with the earth. This concrete, physical meaning dominated for a long time and kept the word grounded in the world of things you could see and touch.
The figurative leap — using 'impact' to mean a powerful effect or influence on something abstract, like a policy's impact on society or a speech's impact on an audience — came much later. This extended meaning grew slowly through the 19th century and then exploded in the 20th century, particularly in business, journalism, and academic writing. By the mid-20th century, 'impact' had become one of the most popular words in professional English, used to describe the effect of almost anything on almost anything else.
The verb form of 'impact', meaning 'to have an effect on something', has attracted criticism from many language experts. Purists argued that 'impact' should remain a noun, and that saying 'this will impact our results' was sloppy or unnecessary when 'affect' existed. However, language rarely listens to its critics, and the verb form is now widely accepted in everyday and professional use. The Latin root 'pangere' also gave English several cousins worth noticing: Latin 'pangere' → Old French 'pais' → English 'peace' (originally meaning something fixed or settled), and Latin 'compingere' (to pack together) → English 'compact', meaning pressed tightly or a small pressed block of powder.