keep
"Keep" is one of those essential English words you will use every single day. It has many meanings, but a few core ideas run through all of them: holding onto something, continuing something, or maintaining a state. Here are the most common and useful senses.
In history, the 'keep' was the strongest, tallest tower at the centre of a castle. It was the last place of defence if enemies broke through the walls. You will mostly see this meaning in history books or fantasy stories.
history / architecture · Formal, more common in older texts and historical contexts