Quinquagesima is the Sunday that sits just before Lent begins — the last ‘ordinary’ Sunday, in the old church calendar, before Ash Wednesday. The name is Latin for something like ‘the fiftieth (day)’: people counted it as about fifty days before Easter. (Lent itself is shorter than that, because Sundays were often not counted as fast days, so the number feels a little off until you know the old way of counting.) It belongs with two other old names, Septuagesima and Sexagesima, roughly ‘seventieth’ and ‘sixtieth’. You will meet it in Anglican and older Catholic calendars, in hymn books, and in history; many modern Catholic parishes dropped the name after the 1960s and just say ‘the Sunday before Lent’. It is a church-calendar word, not everyday talk. People sometimes mix it up with Pentecost (also a ‘fiftieth’ day, but after Easter, and from Greek, not Latin).

四旬期前主日（舊禮儀曆）。勿與「五旬節」（Easter 之後的 Pentecost）搞混。