A crosswalk is a place on a street marked so people on foot can walk across while drivers are supposed to watch for them. You often see white stripes on the road. In many countries those stripes look a bit like a zebra, which is why some people call the same place a zebra crossing. Crosswalk is the usual American word; British English prefers pedestrian crossing or zebra crossing. The thing itself is the same: a bit of road set aside for walkers. Though actually, a crosswalk is not always stripes. Sometimes it is two lines, or lights and a button you press. The important idea is “walkers cross here.” In American English people also use it as a verb, to crosswalk, meaning to walk across at that marked place, but the noun is what you will meet most. It is a practical street word, not slang and not fancy.