This is the 4514th most frequent German word.
nebenbei
"Nebenbei" means "incidentally" or "by the way."
In this sentence, 'nebenbei' is used to indicate an activity being done as a secondary or supplementary action alongside one's primary occupation or study.
Ich arbeite nebenbei in einem Café, um etwas Geld zu verdienen.
I work part-time in a café to earn some money.
Here, 'nebenbei' means 'by the way,' and it introduces an additional and somewhat tangential remark during the discourse.
Nebenbei bemerkt, das Wetter heute ist wirklich schön.
By the way, the weather today is really nice.
In this case, 'nebenbei' implies that something was done in passing or mentioned without emphasis.