Pinpoint means to identify or locate something with exact precision. When a doctor pinpoints the cause of your headache, she figures out the specific reason you're in pain. When a detective pinpoints the time a crime occurred, he narrows it down to the exact minute: 3:47 PM, not “sometime Tuesday afternoon.”

When you pinpoint something, you're being that exact. A scientist might pinpoint which gene causes a particular trait. A historian might pinpoint the moment when a battle turned in favor of one side.

You can also use pinpoint as an adjective meaning extremely accurate or precise: pinpoint accuracy describes hitting exactly what you're aiming at, like an archer splitting an arrow already stuck in the bullseye. A pilot making a pinpoint landing touches down at exactly the right spot on the runway.

The word suggests careful observation and clear thinking. Anyone can make a vague guess, but pinpointing something requires paying close attention to details and evidence until you've eliminated uncertainty.