I am writing some instructions and I want my audience to understand that an amount must be entered in cents / pence / Eurocents / Satoshis etc. Is there a word that describes these small, granular parts of currency?
I'm dealing with non-physical objects, e.g. in an online payments system.
Coinage is generally made up to represent portions of a the smallest bill (also called a note) currency. IE: The amount of funds to be issued does not equal a whole bill denomination so coins represent that portion. For example: The smallest Euro denomination in paper note form is 5euro ... someone needing to pay 4euro will use coins to transfer the value. (in limited cases the smallest note/bill denomination is represented with a coin and in paper form...US is an example...in these instances the coins are rarely used.)
There is no common term that commonly refers to what you are describing. "Coinage" could be used but it is an imprecise term and people still might not get your intention without explanation. Unfortunately the simplest explanation is simply to say "pence, cents, etc.".