A buttress is a structure built against a wall to support it and keep it from falling down. Think of it like a friend leaning their shoulder against your back when you're trying to hold up something heavy: the buttress pushes against the wall from the outside, helping it stay strong and upright.

Medieval cathedral builders used massive stone buttresses because their walls had to hold up incredibly heavy roofs and couldn't do it alone. The flying buttresses you see arching out from famous Gothic cathedrals like Notre-Dame aren't just decorative: they're essential support structures that allowed builders to create walls with huge stained glass windows instead of solid stone. Without buttresses, those magnificent walls would have collapsed under the weight.

The word also works as a verb. When you buttress an argument, you strengthen it with facts and evidence. A lawyer might buttress their case with testimony from multiple witnesses. A scientist might buttress their theory with experimental data. You might buttress your request for a later bedtime by pointing out your improved grades, responsible behavior, and the fact that you've been waking up on time consistently. Just like the physical structure, these supporting pieces help your argument stand strong against challenges.