der Faktor
factor
A circumstance or condition that influences a particular effect or result.
Der menschliche Faktor spielt bei der Sicherheit eine entscheidende Rolle.
The human factor plays a crucial role in safety.

factor
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factor
A circumstance or condition that influences a particular effect or result.
Der menschliche Faktor spielt bei der Sicherheit eine entscheidende Rolle.
The human factor plays a crucial role in safety.

'Faktor' (factor) is often combined with adjectives that emphasize its importance. Common collocations are 'ein wichtiger Faktor' (an important factor), 'ein entscheidender Faktor' (a crucial factor), or 'ein wesentlicher Faktor' (an essential factor).
Die Lage ist ein entscheidender Faktor bei der Wohnungssuche.
Location is a crucial factor when looking for an apartment.
To name the area in which the factor plays a role, the preposition 'bei' with the dative is often used. Another typical construction is 'eine Rolle spielen' (to play a role).
Das Wetter ist ein wichtiger Faktor bei der Planung von Outdoor-Aktivitäten.
The weather is an important factor in planning outdoor activities.
You can clearly recognize the mathematical meaning from the context. When numbers, multiplication, or a product are being discussed, a factor in the mathematical sense is always meant.
Was sind die Faktoren von 21?
What are the factors of 21?
reason / ground
'der Grund' and 'der Faktor' can both explain why something happens or why a result comes about. 'Grund' usually names the cause or reason for an action, event, or state. It often answers the question 'Why?'. 'Faktor' is more about one influence among several. A factor is not always the only reason, but contributes to a result. Learners may confuse the words because both have to do with explanations. As a guide: for a direct reason or justification, use 'Grund'. For an influence within a larger situation, use 'Faktor'.

Bei der Arbeit ist Zeit ein wichtiger Faktor für die Planung.
At work, time is an important factor in planning.
Am Montag erklärt der Arzt, warum Stress ein Grund für die Schmerzen sein kann.
On Monday, the doctor explains why stress can be a reason for the pain.