- apparatus
- appendix
- axis
- datum
- erratum
- focus
- formula
- genus
- larva
- medium
- memorandum
- nebula
- radius
- series
- species
- stratum
- terminus
- vertex
II. FROM THE GREEK.
- analysis
- antithesis
- automaton
- basis
- crisis
- ellipsis
- hypothesis
- parenthesis
- phenomenon
- thesis
Anglicized words.
When the foreign words are fully naturalized, they form their plurals in the regular way; as,—
- bandits
- cherubs
- dogmas
- encomiums
- enigmas
- focuses
- formulas
- geniuses
- herbariums
- indexes
- seraphs
- apexes
Usage varies in plurals of letters, figures, etc.
54. Letters, figures, etc., form their plurals by adding -s or 's. Words quoted merely as words, without reference to their meaning, also add -s or 's; as, "His 9's (or 9s) look like 7's (or 7s)," "Avoid using too many and's (or ands)," "Change the +'s (or +s) to -'s (or -s)."
CASE.
Definition.