8. The principal noun of a compound noun, whether it precedes or follows the descriptive part, is in most cases the noun that changes in forming the plural; as, mothers-in-law, knights-errant, mouse-traps. In a few compound words, both parts take a plural form; as, man-servant, men-servants; knight-templar, knights-templars.

9. Proper names and titles generally form plurals in the same way as do other nouns; as, Senators Webster and Clay, the three Henrys. Abbreviations of titles are little used in the plural, except Messrs. (Mr.), and Drs. (Dr.).

10. In forming the plurals of proper names where a title is used, either the title or the name may be put in the plural form. Sometimes both are made plural; as, Miss Brown, the Misses Brown, the Miss Browns, the two Mrs. Browns.

11. Some nouns are the same in both the singular and the plural; as, deer, series, means, gross, etc.

12. Some nouns used in two senses have two plural forms. The most important are the following:

brotherbrothers (by blood)brethren (by association)
clothcloths (kinds of cloth)clothes (garments)
diedies (for coinage)dice (for games)
fishfishes (separately)fish (collectively)
geniusgeniuses (men of genius)genii (imaginary beings)
headheads (of the body)head (of cattle)
indexindexes (of books)indices (in algebra)
peapeas (separately)pease (collectively)
pennypennies (separately)pence (collectively)
sailsails (pieces of canvas)sail (number of vessels)
shot shots (number of discharges)shot (number of balls)

13. Nouns from foreign languages frequently retain in the plural the form that they have in the language from which they are taken; as, focus, foci; terminus, termini; alumnus, alumni; datum, data; stratum, strata; formula, formulœ; vortex, vortices; appendix, appendices; crisis, crises; oasis, oases; axis, axes; phenomenon, phenomena; automaton, automata; analysis, analyses; hypothesis, hypotheses; medium, media; vertebra, vertebrœ; ellipsis, ellipses; genus, genera; fungus, fungi; minimum, minima; thesis, theses.

Exercise 3

Write the plural, if any, of every singular noun in the following list; and the singular, if any, of every plural noun. Note those having no singular and those having no plural.

News, goods, thanks, scissors, proceeds, puppy, studio, survey, attorney, arch, belief, chief, charity, half, hero, negro, majority, Mary, vortex, memento, joy, lily, knight-templar, knight-errant, why, 4, x, son-in-law, Miss Smith, Mr. Anderson, country-man, hanger-on, major-general, oxen, geese, man-servant, brethren, strata, sheep, mathematics, pride, money, pea, head, piano, veto, knives, ratios, alumni, feet, wolves, president, sailor-boy, spoonful, rope-ladder, grandmother, attorney-general, cupful, go-between.