momentous

Momentous is an adjective describing something of great importance or consequence; the term denotes events or decisions whose effects are lasting and far-reaching. An action may be described as momentous if it changes the course of history, policy, science, or personal life.

Origin and development: Momentous derives from the noun moment with the suffix -ous. The core idea comes from Latin momentum, meaning movement or importance, and the sense of lasting significance was established in English by early modern usage.

Usage notes: The word is common in formal, historical, or rhetorical contexts. It often collocates with 'decision,' 'event,' 'year,' or 'turning point.' It can imply gravitas or solemnity; in everyday speech, 'significant' or 'important' is more common and neutral. Overuse can make prose sound melodramatic.

Examples: The momentous decision to sign the treaty reshaped the region. The discovery proved momentous for medical science.