There are multiple definitions - click on the translation that matches your context.

Vereidigung

Substantiv

full

oath

noun

Comparative law notes

Germany

The better translation for "Vereidigung" is really the "giving of an oath" since the German term refers to the process and not the oath itself.

Definitions of oath

English

a promise that a person will tell the truth (especially in a court of law), especially one that makes reference to God or to a holy book

I must remind you that you are under oath. Think very carefully before answering the question.