| Singular | Plural |
| addendum | addenda |
| agenda | agendas |
| alumnus, alumna | alumni |
| appendix | appendices |
| basis | bases |
| bureau | bureaus |
| campus | campuses |
| consortium | consortia |
| corps | corps |
| criterion | criteria |
| formula | formulas |
| index | indexes (books), indices (science, economics) |
| maximum | maximums |
| medium | mediums (life sciences, art), media (press, IT) |
| memorandum | memoranda |
| millennium | millennia |
| phenomenon | phenomena |
| plus | pluses |
| practicum | practicums |
| premium | premiums |
| quantum | quanta |
| referendum | referendums |
| stimulus | stimuli |
| thesis | theses |