Major feasts of the church year, including the principal feasts, feasts of our Lord, feasts of all apostles, evangelists, and other major saints' days and festivals. The term reflects the early practice of printing Prayer Book calendars in red. These major feasts were included in the Prayer Book calendar and printed with red letters. The term is applied to those feasts for which the BCP provides full propers, including collect, OT lesson, psalm, NT epistle, and gospel. Red-letter days are distinguished from the lesser feasts of the calendar of the church year, which are also known as black-letter days and printed with black letters. In Prayer Books with single-color printing, major feasts are printed in bold type, and lesser feasts are printed in lightface type. See The Calendar of the Church year (BCP, pp. 19-30).
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from "An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians," Don S. Armentrout and Robert Boak Slocum, editors.