der Ellbogen
elbow
The joint that connects the upper arm with the forearm.
Ich habe mich am Ellbogen gestoßen und jetzt ist er blau.
I bumped my elbow, and now it is bruised.

elbow
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elbow
The joint that connects the upper arm with the forearm.
Ich habe mich am Ellbogen gestoßen und jetzt ist er blau.
I bumped my elbow, and now it is bruised.

'Ellbogen' (elbow) is composed of 'Elle' (ulna), a bone in the forearm, and 'Bogen' (bow/arc). So the word figuratively describes the 'Bogen' (arc) or bend in the arm.
Beim Sturz hat er sich den Ellbogen verletzt.
He injured his elbow when he fell.
In connection with the body part, typical verbs are 'sich den Ellbogen stoßen' (to bump one's elbow), 'sich auf die Ellbogen stützen' (to lean on one's elbows), or 'den Ellbogen anwinkeln' (to bend one's elbow).
Er stützte sich nachdenklich auf die Ellbogen.
He leaned thoughtfully on his elbows.
The idiom 'die Ellbogen benutzen' (to use one's elbows) or 'die Ellbogen einsetzen' (to use one's elbows) means to ruthlessly pursue one's own goals. In this expression, the word is always used in the plural.
Wer in dieser Firma Karriere machen will, muss seine Ellbogen einsetzen.
Anyone who wants to make a career in this company has to use their elbows.
elbow
'Ellenbogen' and 'Ellbogen' mean the same thing. Both words refer to the joint in the middle of the arm. Both forms can also be used in the figurative sense, when someone pursues their goals ruthlessly. The words are easy to confuse because they look almost the same and are used in the same way. The difference is mainly in the spelling: 'Ellenbogen' is the longer form, 'Ellbogen' the shorter one. In terms of meaning, there is no important difference here.

Im vollen Zug hat mir jemand mit dem Ellbogen in die Seite gestoßen.
On the crowded train, someone jabbed me in the side with their elbow.
Nach dem Sturz tut mir der Ellenbogen weh.
After the fall, my elbow hurts.