reverse

Imagine building a tower with LEGO bricks. To reverse that process is to take the bricks apart in the exact opposite order from how you put them together, going backward from the finished tower. It can mean physically moving something backward, like reversing a car into a tight parking space. But it is more than just movement. You might reverse a decision, meaning you change your mind and do the opposite of what you first planned. A detective might work backward from the evidence to figure out how an event started. Sometimes, a story is even told in reverse order, beginning with the ending and finishing at the beginning.

To reverse something means to change its direction, order, position, or result so it goes back or becomes the opposite of what it was before. It is a flexible word that applies to both physical actions and abstract ideas.

Think about driving: to reverse a car is to move it backward. In finance, you might reverse a charge on your credit card, which undoes a previous payment. Even in the culinary world, a chef might reverse sear a steak—starting with a low, slow temperature and finishing with high heat, which is the opposite of the traditional method of searing first.

Figuratively, reverse often means to cancel, undo, or officially change an earlier action. In a courtroom, a higher court might reverse a conviction, meaning it overturns the earlier legal decision. On a broader scale, people also talk about reversing a trend, such as trying to reverse years of economic decline and move things in a better direction again.

In science and technology, the word has specific technical meanings. Reverse osmosis is a water purification process that forces liquid through a membrane against its natural flow. In genetics, scientists study the reverse transcriptase enzyme to understand how certain viruses replicate. Rooted in the Latin revertere, meaning "to turn back," the word reverse always implies a turning around, an undoing, or a complete shift in direction.