Modernism, in this use, is a way of making art and buildings that threw out old decoration and leaned on simple shapes and new factory-made stuff — steel, glass, concrete, plastic. Learner’s books often pin it to the 1940s to the 1960s: clean lines, boxy towers, furniture with thin legs. The feeling is “we live in a new age, so the look should be new too” — no extra flowers carved into the wall, no copying of old palaces. You meet the word in art class, design, and architecture. Fairly formal. Though actually, those dates are tidier than the real story. Many teachers use Modernism for a longer wave that starts much earlier in the 1900s, when painters and writers were already breaking the old rules; they may use other names for the later, cleaner buildings. The sense here is that later simple-shape, man-made-material look. It is not “anything from now.” A painting from last year is of today; it is not modernism just because it is new. And it is not the everyday word modern, as in a new phone.