Learn German: Warten Sie bitte einen Augenblick.

This is an adverbial accusative. In German, definite expressions of time, duration, or distance that are not introduced by a preposition take the accusative case. Since der Augenblick (the moment) is a masculine noun, its article becomes einen to express how long the wait should be.

Can I say für einen Augenblick instead?

Yes, für einen Augenblick is grammatically correct and means the exact same thing. However, dropping the preposition für and relying solely on the adverbial accusative is extremely common and usually sounds more natural in everyday spoken German.

What is the literal meaning of the word Augenblick?

It literally translates to an 'eye glance' or 'blink of an eye'. It is a compound noun made from das Auge (the eye) and der Blick (the look or glance). It is the standard, everyday German word for a 'moment' or 'instant'.

Why is the pronoun Sie placed after the verb Warten?

This is a quick refresher on the formal imperative (command) mood. When instructing someone you address formally with Sie, the verb is placed in the very first position, immediately followed by the pronoun Sie.