A periodical is a publication that is released at regular intervals, such as daily, weekly, MONTHLY, or yearly. Examples of periodicals include books, journals, magazines, bulletins, and organs. MONTHLY is a periodical that is released once a month, while a BOOK is a periodical that is released in the form of a printed or electronic publication. A JOURNAL is a periodical that is published by a professional organization or academic institution and contains scholarly articles. An ORGAN is a periodical that is published by a religious organization or denomination. MAG is a periodical that is published in the form of a MAGAZINE. A BULLETIN is a periodical that is published by an organization or institution and contains news and announcements. Finally, a MAGAZINE is a periodical that is published in the form of a printed or electronic publication and contains articles, stories, and other content.