Not that this matters much

but yes, it's "rap" (singular) or "raps" (plural). So we have ...
(de) Rappen / Franken (same for singular and plural)
(fr) centime / franc
(it) centesimo / franco
(rm) rap / franc
That is also why the small denomination coins only have digits to indicate the face value. The small "B" at the bottom is Swissmint's Berne mintmark.
Christian