der Pen
pen injector
A small, pen-like device for administering medication, especially insulin.
Diabetiker benutzen oft einen Pen, um sich Insulin zu spritzen.
Diabetics often use a pen injector to inject themselves with insulin.

pen
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pen injector
A small, pen-like device for administering medication, especially insulin.
Diabetiker benutzen oft einen Pen, um sich Insulin zu spritzen.
Diabetics often use a pen injector to inject themselves with insulin.

'Pen' is a word from English. In German, however, it normally does not refer to an ordinary writing instrument with ink, but to a special pen-shaped device for technical or medical purposes.
Für mein neues Grafiktablett brauche ich einen speziellen Pen.
I need a special stylus for my new graphics tablet.
You can tell what kind of 'Pen' it is from the context. Words like 'Insulin' (insulin) or 'spritzen' (to inject) point to a medical device, while 'Tablet' (tablet) or 'zeichnen' (to draw) refer to a stylus.
Der Arzt zeigte ihr die richtige Anwendung des neuen Pens.
The doctor showed her how to use the new pen injector correctly.
The use of 'Pen' for a USB flash drive is becoming outdated today. In modern colloquial speech, the terms 'USB-Stick' (USB flash drive) or simply 'Stick' (flash drive) are much more common.
Hast du die Dokumente auf einem Stick gespeichert?
Did you save the documents on a flash drive?
In a medical context, 'Pen' is often combined with the medication it contains. The most common compound is 'Insulin-Pen' (insulin pen).
Moderne Insulin-Pens sind sehr einfach zu bedienen.
Modern insulin pens are very easy to use.
pen / pin / apprentice
'der Stift' and 'der Pen' can both look like a long, narrow device that you write or draw with. 'Stift' is the normal German word for writing and drawing instruments on paper. 'Pen' is used more for special devices, especially a stylus for a tablet or graphics tablet. It can also occur in other specialist fields, for example with medication. Learners may confuse the words because in English, 'pen' means a normal writing instrument. In German, you usually say 'Stift' for paper; in technology, 'Pen' is possible and often more precise.

Im Grafikdesign-Kurs zeichnet Lena mit einem Pen auf dem Tablet.
In the graphic design course, Lena draws on the tablet with a stylus.
Kannst du mir einen Stift geben, damit ich die Adresse notiere?
Can you give me a pen so I can write down the address?