The word "guide" comes from the Old French "guider" meaning "to guide, lead, conduct". The noun form of the word has been in use since the 14th century, while the verb form has been in use since the 16th century. The word is commonly used in the context of travel and tourism, where a guide is a person who leads others on a journey. It is also used more broadly to refer to anything that helps someone make a decision or form an opinion.