Where does “Adventkalender” come from?

Adventkalender (German) comes from German Advent, from Middle High German advent, from Latin adventus, from Latin adveniō, from Latin ad-, from Latin īn-, from Latin în, from Latin en — in.

Ancestry of “Adventkalender”, step by step

Adventkalender traces back through two separate lines of ancestry.

via German Advent

StepLanguageWordMeaning
1GermanAdventAdvent
2Middle High GermanadventAdvent
3Latinadventusarrival, approach, advent; Advent
4Latinadveniōto come to, to arrive
5Latinad-to; usually prefixed to verbs, in which cases it...
6Latinīn-un-, non-, not
7Latinînin, at, on, upon, from (space)
8Latinenlookǃ beholdǃ; reallyǃ?; come onǃ
9Proto-Italicenin
10Proto-Indo-Europeanh₁énin

via German Kalender

StepLanguageWordMeaning
1GermanKalendercalendar; agenda, scheduler, planner; omasum
2Latincalendāriuman account book or debt book
3LatinCalendaeAbbreviation Cal; astronomical new moon; calends
4Latincalāre
5Latinchalāre
6Ancient GreekχαλάωI slacken; I loosen; I become slack; I become...
Every word from Proto-Indo-European h₁én