die Treppe
stairs
A structure made of steps that makes it possible to move on foot between different levels of a building or area.
Vorsicht, die letzte Stufe der Treppe ist kaputt.
Careful, the last step of the stairs is broken.

stairs
Loading your saved state.
stairs
A structure made of steps that makes it possible to move on foot between different levels of a building or area.
Vorsicht, die letzte Stufe der Treppe ist kaputt.
Careful, the last step of the stairs is broken.

The noun 'die Treppe' (stairs) is closely related to the verb 'treten' (to step). So a staircase is a device that you step on in order to get up or down.
Er trat vorsichtig auf die nasse Treppe.
He stepped carefully onto the wet stairs.
Verbs of movement are often used with 'Treppe' (stairs). Typical phrases are 'die Treppe nehmen' (to take the stairs), 'eine Treppe hinaufgehen' (to go up a staircase), or 'eine Treppe hinuntersteigen' (to go down a staircase).
Wir nehmen die Treppe, weil der Aufzug besetzt ist.
We're taking the stairs because the elevator is occupied.
To indicate direction on stairs, a verb is often combined with adverbs like 'hinauf' (up), 'hinunter' (down), 'hoch' (up), or 'runter' (down).
Die Kinder rannten die Treppe hinauf.
The children ran up the stairs.
step / level
'die Stufe' and 'die Treppe' both belong to the area where you go up or down. The difference is simple: a 'Stufe' is just one single step. A 'Treppe' consists of several steps and connects two levels. Learners may confuse the words because both are used when walking inside a building. If you mean just one step, you say 'Stufe'. If you mean the whole structure, you say 'Treppe'.

Herr Wagner nimmt im Büro die Treppe, weil der Aufzug voll ist.
Mr. Wagner takes the stairs at the office because the elevator is full.
Auf der letzten Stufe liegt ein kleiner Stein.
There is a small stone on the last step.