Definition of set in

The phrase "set in" is a prepositional phrase that is used to describe a situation where something begins to occur or become established over a period of time. The origin of this phrase can be traced back to Old English, specifically to the words "sittan" and "in". The Old English word "sittan" means "to sit" and "in" has a variety of meanings, including "inside" and "within". When these two words were combined in Old English, they created the phrase "sittan in", which referred to someone or something being located or positioned inside a place. Over time, the meaning of "set in" evolved to describe a situation where something becomes firmly established or persistent. For example, "the rain set in" implies that the rain began and then continued for some time, suggesting that it was not a temporary occurrence. Today, "set in" is still used in a variety of ways, such as describing the symptoms of an illness ("the pain set in"), a change in the weather ("the fog set in"), or a person's emotions ("her tears set in"). In each case, it signifies that the event in question is becoming more deeply ingrained or entrenched over time.