Origin: Germanic Old English suffix
Readership has 3 different meanings across 1 category:
the audience reached by written communications (books or magazines or newspapers etc.)
"The magazine's readership has grown steadily since they switched to a monthly digital format."
The collected readers of a publication.
"The new appointment was not to the editorial board but rather as readership in the royal library, where he would catalog ancient manuscripts for the king."
The office or position of a Reader