I need to print out a small tag of 10cm x 4cm (w x h) but I'm not sure what to put in the resolution. I set the width and height to 'centimeters' as measurement but not sure what to put as resolution. Is it 300 pixes/inch or 300 pixels/centimeter (since I used centimeters as a unit)?
As Rafael points out, 300dpi is the same as 118dpc (dots per centimeter?)
Note that 300dpi is 'standard' for printing photographs. If your Artwork is text or line-art based, however, you want to be printing at much higher resolutions. 600dpi at minimum (if not higher at 1200dpi for high quality printing).