Definition of tell on

The phrase "tell on" is a medieval English expression that originated from the Old Norse word "talan," meaning to accuse or prosecute. When the Anglo-Saxons adopted the term in 10th-century England, they adapted it to "tellan," meaning to accuse or betray. As English began to evolve, "tellan" transformed into "tellen" in Middle English, and by the 16th century, we see the variant "telle" in written records. "Telle" was used to indicate revealing or exposing a secret or wrongdoing. Through the centuries, the phrase "tell on" has evolved in usage, often being used to mean betraying someone's secrets or confidential information. While other variations, such as "tell upon" and "tell against," still exist, the common usage of the idiom "tell on" has become an ingrained part of everyday language in British and American English.