
das Gefängnis
prison
A building or institution in which people who have committed a crime are locked up.
Der Verurteilte wurde in das örtliche Gefängnis gebracht.
The convicted man was taken to the local prison.
prison
Loading your saved state.

prison
A building or institution in which people who have committed a crime are locked up.
Der Verurteilte wurde in das örtliche Gefängnis gebracht.
The convicted man was taken to the local prison.

prison sentence
The punishment of being locked up for a certain period of time; a custodial sentence.
Er bekam drei Jahre Gefängnis für den Raubüberfall.
He got three years in prison for the robbery.
The word derives from the verb 'fangen' (to catch). The prefix 'Ge-' and the ending '-nis' often form nouns that describe a state or place. A 'Gefängnis' (prison) is therefore a place where one is 'gefangen' (captured/imprisoned).
Die Polizei konnte den Dieb schnell fangen.
The police were able to catch the thief quickly.
Pay attention to the case with the preposition 'in': movement toward a place requires the accusative ('ins Gefängnis kommen' — to go to prison), while being in a place requires the dative ('im Gefängnis sein' — to be in prison).
Er musste für zwei Jahre ins Gefängnis.
He had to go to prison for two years.
When 'Gefängnis' (prison) describes the type of punishment, it is often used without an article and together with a time expression. Typical verbs here are 'bekommen' (to get/receive) or 'verurteilt werden zu' (to be sentenced to).
Der Angeklagte bekam eine Strafe von fünf Jahren Gefängnis.
The defendant got a sentence of five years in prison.
The meaning 'Gebäude' (building) is intended when it is about a concrete place (e.g. 'das Gefängnis besuchen' — to visit the prison). The meaning 'Strafe' (punishment) is intended when it is about a sentence or a duration (e.g. 'drei Jahre Gefängnis' — three years in prison).
Das alte Gefängnis in der Stadt ist heute ein Museum.
The old prison in the city is now a museum.
construction / building
Both Bau and Gefängnis can refer to the place where people are locked up. Bau is a casual, colloquial term for this, while Gefängnis is neutral and unambiguous. Use Gefängnis in factual situations and Bau only in casual or deliberately colloquial language.

Nach dem Urteil musste der Angeklagte zurück ins Gefängnis.
After the verdict, the defendant had to go back to prison.
Nach dem Urteil musste der Angeklagte zurück in den Bau.
After the verdict, the defendant had to go back to jail.