Totality means the whole of something, complete and entire. When scientists study the totality of evidence, they examine every single piece of information available, including data that might contradict their preferred theory. When a teacher considers the totality of a student's work over the semester, she looks at everything: tests, homework, class participation, and improvement over time.

The word emphasizes completeness. Saying “we need to understand the totality of the problem” means you must look at every piece to find the real answer. You need the whole picture.

In astronomy, totality has a special meaning: it's the brief period during a solar eclipse when the moon completely blocks the sun. For a few minutes, day turns to an eerie twilight as the moon's shadow sweeps across the Earth. People travel thousands of miles to experience totality because a partial eclipse, while interesting, can't compare to those mysterious minutes when the sun disappears completely.