A washcloth is a small square of towel cloth, about the size of your hand, that you wet and soap and rub over your face and body in the bath or shower. It is American English. In Britain the same thing is a "flannel", and in Taiwan the small towel most families use for this is close enough that "washcloth" is the word you want when writing to an American. Hotels put one folded next to the bigger towels; parents keep a few for wiping a child's sticky face. It is not a cleaning cloth for tables or floors — that would be a "dishcloth" or a "rag". A useful travel detail: many hotels outside America do not supply one at all, so American travellers often pack their own.