die Schlüsselrolle
key role
A decisive, central, or very important function or position in a particular context, process, or system.
Die Zeugenaussage spielte im Prozess eine Schlüsselrolle.
The witness statement played a key role in the trial.

key role
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key role
A decisive, central, or very important function or position in a particular context, process, or system.
Die Zeugenaussage spielte im Prozess eine Schlüsselrolle.
The witness statement played a key role in the trial.

The word consists of 'Schlüssel' (key) and 'Rolle' (role). Here, 'Schlüssel' (key) metaphorically stands for something that enables access to a solution or success. A 'Schlüsselrolle' (key role) is therefore a role that is decisive for success.
Die richtige Ernährung ist der Schlüssel zu guter Gesundheit.
The right diet is the key to good health.
The element 'Schlüssel-' (key) is used in many words to mark central importance. If you recognize this pattern, you will also understand words like 'Schlüsselfigur' (key figure/most important person), 'Schlüsselmoment' (key moment/decisive moment), or 'Schlüsseltechnologie' (key technology).
Die Entdeckung des Penicillins war ein Schlüsselmoment in der Medizingeschichte.
The discovery of penicillin was a key moment in the history of medicine.
The most common and important collocation is 'eine Schlüsselrolle spielen' (to play a key role). Other typical verbs are 'eine Schlüsselrolle einnehmen' (to occupy/take on a key role) or 'eine Schlüsselrolle haben' (to have a key role).
Die Digitalisierung spielt in der modernen Wirtschaft eine Schlüsselrolle.
Digitalization plays a key role in the modern economy.
position
'Position' and 'Schlüsselrolle' can both describe what function someone has in a team, a company, or a process. 'Position' is neutral and simply means a role or job within an order or structure. 'Schlüsselrolle' says much more: this person or function is especially important and decisive for success. Learners may confuse the words because an important position can also be a key role. But not every position is automatically a 'Schlüsselrolle'.

Die Ärztin spielt eine Schlüsselrolle, weil sie alle wichtigen Entscheidungen koordiniert.
The doctor plays a key role because she coordinates all the important decisions.
Hannes hat im neuen Projekt eine feste Position im Marketingteam.
Hannes has a fixed position in the marketing team in the new project.