Other loan nouns

As can be seen from the above list some loan nouns may have two plural forms: the English plural and the original foreign one:

memorandum	memoranda memorandums	focus	foci focuses
curriculum	curricula curriculums
formula	formulae formulas
cherub	cheribum cherubs

There is a tendency to use the regular English plural forms in fiction and colloquial English and the foreign plural in academic or learned language.

Sometimes different plural forms have different meanings:

index	indexes (list of contents of books) indices (a mathematical term - показатель)
genius	geniuses (men of talent) genii (fabulous spirits guarding a place - духи, домовые)