Definition of be onto

The expression "be onto" is a British and Australian colloquialism that originated in the late 19th century. The original meaning of the phrase was "catch onto" or "get onto," and it referred to the act of recognizing or comprehending something that others had not yet understood. The exact origins of the phrase are disputed, but it is believed to have evolved from the Australian slang term "be on to," which was used to indicate being aware of a situation or plan. Some speculate that the expression may have originated from the mining industry, where it was used to describe finding a source of valuable minerals. By the early 20th century, "be onto" had become a widespread expression in both British and Australian English, and it was commonly used to signify being on the right path to solving a problem or discovering something new. While the usage of the phrase has become less common in more formal English, it remains an important part of the informal lexicon used by speakers in these regions.