pyramid:a system, society, company etc that is organized in different levels, so that there is a small number of people at the top and a much larger number of people at the buttom
At the buttom of the pyramid are the poor.
meteorite:a piece of rock that has fallen from space and landed on the ground
demise: the end of something that used to exist; the death of a person
the demise of the typewriter in this computer age
the imminent demise of the local newspaper
tribe: a large group of related families who live in the same area and share a common language, religion, and customs
Native American tribes
deteriorate: to become worse
The weather deteriorated rapidly so the game was abandoned.
Ethel's health has deteriorated.
Armageddon: a battle in the future that will destroy the world
a nuclear Armageddon
Doomsday: the time in the future when some people believe that the world will end
till/untill Doomsday: for a very long time
You could wait till Doomsday and he'll never show up.
lunatic: someone who behaves in a crazy or very stupid way
Some lunatic was driving on the wrong side of the road.
(just) in case: in order to be prepared for somthing that may happen
Take an umbrella in case it rains.
I'll make some sandwiches, just in case we get hungry later on.