adverb
yesterday
A1
gestern means 'yesterday', a temporal adverb referring to the previous day. It's uninflected, takes no articles; often combines with time expressions (gestern Abend). Word order: commonly sentence-initial or in second position. Not irregular; no gender or plural, used in both formal and informal registers.
Examples
Gestern blieb die Schule geschlossen, obwohl der Unterricht normalerweise stattfand.
Yesterday the school stayed closed, although lessons normally took place.
Gestern war ich im Kino.
I was at the cinema yesterday.
Details
Mnemonics
Picture yesterday's calendar page torn off — that's 'gestern'
gestern ~ 'guest-turn' — imagine a guest visiting yesterday