Definition of the word unlisted

The word "unlisted" has its origins in the early 19th century. In the 1820s, the first telephone directories were created, listing the names and phone numbers of subscribers. Those who didn't want their numbers publicly available would deliberately avoid subscribing or wouldn't list their numbers in these directories. Over time, "unlisted" became a term to describe phone numbers that weren't included in these directories. In the mid-20th century, as telephone directories became more comprehensive, the term "unlisted" took on a broader meaning. It referred to any phone number that was not publicly accessible or not available for directory assistance. The rise of private numbers and caller ID further solidified the usage of "unlisted" to describe numbers that were intentionally kept from public view. Today, the term is commonly used in various contexts, including phone numbers, email addresses, and other forms of contact information, to describe information that is not publicly disclosed or easily accessible.