A kind of paint made by mixing coloured powder with something thick and sticky that dries hard — most often egg yolk, which is why you will also hear "egg tempera". Painters in Europe used it for hundreds of years before oil paint took over in about the 1400s, so most very old religious paintings on wooden boards are tempera. It dries fast and gives clear, bright, rather flat colour, and once dry it does not yellow the way old oil paint does. The word also names the technique, not only the liquid: "painted in tempera". You will meet it in art class, in museums, and on the little labels beside paintings. School art shops also sell "tempera paint" for children, though that modern kind usually has no egg in it at all — the name stuck.