In the western Liturgical year, Lady Day is the traditional name of the Feast of the Annunciation of the Blessed Virgin (25 March) in some English-speaking countries. It is the first of the four traditional English quarter days. The "Lady" is the Virgin Mary. The term derives from Middle English, when some nouns lost their genitive inflections. "Lady" would later gain an -s genitive ending, and therefore the name means "Lady's day."
Non-religious significance 
In England, Lady Day was New Year's Day up to 1752 when, following the move from the Julian Calendar to the Gregorian Calendar, 1 January became the start of the year. A vestige of this remains in the United Kingdom's tax year, which starts on 6 April, i.e. Lady Day adjusted for the lost days of the calendar change (until this change Lady Day had been used as the start of the legal year). (This should be distinguised from the liturgical and historical year. It appears that in England and Wales, from at least the late 14th Century, New Year's Day was celebrated on 1 January as part of Yule.)
As a year-end and quarter day that conveniently did not fall within or between the seasons for ploughing and harvesting, Lady Day was a traditional day on which year-long contracts between landowners and tenant farmers would begin and end in England and nearby lands (although there were regional variations). Farmers' time of "entry" into new farms and onto new fields was often this day. As a result, farming families who were changing farms would travel from the old farm to the new one on Lady Day. After the calendar change, "Old Lady Day" (6 April), the former date of the Annunciation, largely assumed this role. The date is significant in some of the works of Thomas Hardy, e.g., Tess of the d'Urbervilles and Far from the Madding Crowd.
The logic of using Lady Day as the start of the year is that it roughly coincides with Equinox (when the length of day and night is equal); many ancient cultures still use this time as the start of the new year, for example, the Iranian new year. In some traditions it also reckons years A.D. from the moment of the Annunciation, which is considered to take place at the moment of the conception of Jesus at the Annunciation rather than at the moment of his birth at Christmas.
In Swedish the word våffla is attested since 1642 and derives from the German Waffel  but is possibly associated by [our Swedish] ancestors with Vår Fru (The Virgin Mary). Waffles are even today in a large number of Swedish households commonly served on Våffeldagen, that is to say, on Lady Day, which is observed the 25th of March.
See also 
- See Sir Gawain and the Green Knight Fytte Three
- Adams, Leonard P. "Agricultural Depression and Farm Relief in England, 1813–1852" Reviewed in Journal of the Royal Statistical Society, 95(4):735-737 (1932)
- "The Tenant League v. Common Sense" Irish Quarterly Review 1(1):25-45 (March, 1851)
- Nationalencyklopedins ordbok
- Nordiska museet - Marie bebådelsedag och våffeldagen, 25 mars