Mittelalter

German

From Middle High German mittel alter (“middle age [of life]”), at least since the 16th century also univerbated. By surface analysis, mittel- (“mid, middle”) +‎ Alter (“age”). The historic sense dates from the 18th century and is a calque of New Latin medium aevum, from the idea that it was the interim between Antiquity and Modernity.

das Mittelalter n (proper noun, strong, usually definite, definite genitive des Mittelalters)

Mittelalter n (strong, genitive Mittelalters, no plural)

(figurative) dark ages, an uncultured or barbaric era (from a misrepresented view with roots in Renaissance and Protestant thought)
Wenn das so weitergeht, fallen wir zurück in finsterstes Mittelalter!
If it goes on like this, we’ll slide back into the deepest dark ages!
(now rare and mostly humorous) middle age (of life)
Synonym: mittleres Alter
(by extension, collective, colloquial, derogatory) middle-aged people
In dem Laden hängt mir zu viel Mittelalter ab.
There are too many middle-agers hanging out at that place for my taste.

Declension of Mittelalter [sg-only, neuter, strong]