A newsletter is a regular, periodic publication that provides information to a specific group of people. You might subscribe to a newsletter that gives you shopping tips, or one that features information about caring for your pet ferret.
Belonging to a club or a church sometimes includes receiving monthly newsletters full of news and upcoming events. Schools often send newsletters home to students' parents, so they know what's happening during the semester. Many newsletters are printed on paper and sent through the mail, while others are distributed via email. The term newsletter was common in the seventeenth century, but it fell out of favor for many years until a revival in the twentieth century.