Where does “Trinity Monday” come from?

Trinity Monday (English) comes from English Trinity, from Middle English trinite, from Anglo-Norman trinite, from Latin trīnitās, from German Dreieinigkeit, from German Einigkeit, from German -keit, from German -heit.

Trinity Monday (English): The Monday which directly follows Trinity Sunday, and starts Trinitytide (the liturgical tide that lasts till Advent)

Definitions

  1. The Monday which directly follows Trinity Sunday, and starts Trinitytide (the liturgical tide that lasts till Advent)

Ancestry of “Trinity Monday”, step by step

Trinity Monday traces back through two separate lines of ancestry.

via English Trinity

StepLanguageWordMeaning
1EnglishTrinityIn Christian belief, the three persons of the Godhead: the Father, Son and Holy Spirit
2Middle EnglishtriniteA triad; a trinity
3Anglo-Normantrinite
4Latintrīnitāsthreeness; the state of being three
5GermanDreieinigkeitTrinity
6GermanEinigkeitunity; consensus, agreement
7German-keitAlternative form of -heit; -ness, -ty; -ty
8German-heitConverts an adjective into a noun and usually...
9Middle High German-heitness, -ity, -hood; forms nouns from adjectives, denoting the abstract quality of the adjective
10Old High German-heitnature, character
11Proto-West Germanic-haiduhood
12Proto-Germanichaiduzmanner, way; personality, character; appearance
13Proto-Indo-European(s)kayt-

via English monday

StepLanguageWordMeaning
1EnglishmondayThe second day of the week in many religious traditions, and the first day of the week in systems using the ISO 8601 norm. It follows Sunday and precedes Tuesday
2Middle EnglishMondayMonday second day of the week
3Old Englishmōnandæġday of the moon
4Proto-Germanic*mānini dag
5Latindies LūnaeMonday
6Ancient Greekσελήνηmoon; month; a moon-shaped cake
7Ancient GreekΣέλαςlight, brightness, the bright flame or blaze of fire
Every word from Proto-Indo-European (s)kayt-
Trinity Monday — Etymology, Origin & Word History | Etymology Explorer