scan

To scan is to examine something by moving across it in a quick or systematic way in order to find information, notice a feature, or check for a problem. It is an interesting verb because it can suggest different speeds. You can scan a newspaper quickly to catch the main headlines, or a scientist can scan a specimen slowly and carefully under a microscope. In both cases, the main idea is the same: attention moves across a larger whole to pick out something important.

The meaning has expanded with modern technology. We use "scan" to describe how devices read, capture, or check data. A scanner can make a digital copy of a paper document or photo. A cashier can scan a barcode so the system recognizes the item and price. Security software can scan files or networks for danger. In medicine, doctors use the noun "scan" for images made by machines such as CT or MRI systems, which let them look inside the body.

The word also has an older use in literature. To "scan" a poem meant to examine its rhythm and meter. That older meaning also fits the core idea of checking something in an ordered way to understand its structure.

So, whether you are a student scanning a textbook for an answer, a radar system scanning the sky for aircraft, or a machine scanning a page into a computer, the word points to the same basic action: moving across something with focused attention to find, read, capture, or detect what matters.