The word "according to" is a phrase used to indicate the source of information or to reference someone’s opinion or point of view. It implies that what follows is based on what someone has said, written, or believes. For example, "According to the weather report, it will rain today."
The phrase "according to" comes from Middle English, where "according" is derived from the verb "acorde," meaning to agree, and "to" is a preposition. The phrase collectively means "in agreement with" or "in relation to."