Orthogonal means at right angles to something else, forming a perfect 90-degree corner like the edges of a book or the intersection of two walls in a room. In geometry, when two lines are orthogonal, they meet at exactly 90 degrees. Perpendicular lines are orthogonal to each other.

The word comes from mathematics but has spread to other fields. In science and engineering, orthogonal describes things that are completely independent from each other, not affecting one another at all. When scientists design experiments with orthogonal variables, they're making sure each factor can be studied separately without interference, like testing both temperature and pressure in ways where changing one doesn't automatically change the other.

In everyday conversation, people sometimes use orthogonal to mean “completely separate” or “unrelated.” If your friend suggests getting pizza and you respond by talking about tomorrow's weather, they might say your comment is orthogonal to the discussion: not wrong exactly, just pointing in a totally different direction that doesn't connect to the topic at hand.

The word sounds complicated, but the core idea is simple: things that are orthogonal either meet at right angles or operate independently without interfering with each other.