A toaster is an appliance for browning bread by radiant heat — most familiarly the electric pop-up toaster with vertical slots, a spring-loaded carrier that lowers the slices, and a timer or browning control that ejects them when done. Heating elements on both sides toast the bread evenly; wider slots handle bagels and thick slices. Toasting transforms bread through Maillard reactions and caramelisation, creating the crisp, nutty crust that makes toast greater than bread. Safety points are real: crumbs accumulate and can ignite, so the crumb tray needs emptying, and metal implements must never be poked inside while plugged in. Conveyor and conveyor-belt toasters serve the same function in catering at volume.