The 'N' when naming compunds

Hey guys, basically we've started organic chemistry in school(at A2) and we have been naming compounds, in class my teacher began using the letter N when it came to naming compounds from some diagrams.

Could anyone explain what the use of the letter of the N is as my teacher's explanation did not help at all?

Thanks in advance.

Your teacher could be referring to N substituted amides?

Thanks for the insight but what does the N- bit stand for?

Well, when you have something like N-ethylbutanamide, all the N means is that the nitrogen atom is connected to the ethyl group (prefix of the name of the compound). I've highlighted the group in bold below.

So it would be something like

CH3CH2CHCONHCH2CH3

IF you see my point now?