Canto, domino (os or oes), duodecimo, halo, junto, lasso, memento, octavo, piano, proviso, quarto, salvo, solo, two, tyro, zero (os or oes).
Nouns in o preceded by a vowel add s.
Bamboo, cameo, cuckoo, embryo, folio, portfolio, seraglio, trio.
Common nouns [Footnote: See Rule 2, Lesson 127. In old English, such words as lady and fancy were spelled ladie, fancie. The modern plural simply retains the old spelling and adds s,] in y after a consonant change y into i and add es without increase of syllables. Nouns in y after a vowel add s.
+Direction+.—Form the plural of each of the following nouns:—
Alley, ally, attorney, chimney, city, colloquy, [Footnote: U after q is a consonant] daisy, essay, fairy, fancy, kidney, lady, lily, money, monkey, mystery, soliloquy, turkey, valley, vanity.
The following nouns change f or fe into ves.
+Direction+.—Form the plural of each of the following nouns:—
Beef, calf, elf, half, knife, leaf, life, loaf, self, sheaf, shelf, staff, [Footnote: Staff (a stick or support), staves or staffs; staff (a body of officers), staffs. The compounds of staff are regular; as, flagstaffs.] thief, wharf, [Footnote: In England, generally wharfs.] wife, wolf.
The following nouns in f and fe are regular.