When the prefix co- is followed by a consonant it does not always take the hyphen. Usage allows contemporary, co-partner, and correspond, as well as co-worker and co-respondent.
The dieresis should be preferred where, in words not compound, the vowel o is doubled, forming a separate syllable, as in epizoötic, laocoön, zoölogy, zoöphyte.
POINTS OF THE COMPASS
Useless hyphened words are often made in naming some of the points of the compass, as north-east, north-west, south-east, south-west, which are better as consolidated words (northeast, northwest, etc.). A hyphen is needed only when one of the words is repeated, as in north-northeast, south-southwest.
FRACTIONS AND NUMERALS
Simple fractions, like one half, two thirds, even sixteenths, ten thousandths, need no connecting hyphen; they are more clearly expressed when numerator and denominator are kept separate and printed as two disunited words. But two numerals may be compounded by the aid of the hyphen when they are needed to qualify a following noun, as in one-half interest, two-third share, seven-sixteenth division.
When the fraction is complex, as in three seventy-ninths or thirty-eight thousandths, the hyphen
