What is the term for a sudden seizure of political power in a nation?

The term "coup d'état" refers specifically to a sudden and often illegal seizure of power from a government. It typically involves a small group, often from within the existing government or military, who overthrow the current leadership. Unlike a revolution, which usually involves widespread support from the populace and major societal changes, a coup is generally executed by a relatively small faction aiming to replace those in power without necessarily altering the foundational political structure of the state.

In a coup, the change of power is often abrupt, and it may not involve a full-scale uprising or armed conflict, although it can lead to violence. The key characteristic of a coup d'état is that it aims for an immediate and swift takeover, often bypassing the usual processes of political change. This distinguishes it from other terms like insurrection or uprising, which typically suggest a broader or more grassroots movement involving larger segments of society.