noun
Etymology: p probably abbreviation of postal; from its being the same size as former small-sized United States postal cards
: a slip of paper approximately three by five inches in size used in library filing
noun
Etymology: p probably abbreviation of postal; from its being the same size as former small-sized United States postal cards
: a slip of paper approximately three by five inches in size used in library filing
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012