The Penguin Dictionary of American English Usage and Style : A ...

52 capitalization
an administering city and assets and all
the rest is capital—with a in the third syllable.
Both words originated in caput, Latin
for head. The ancient temple of Jupiter
on the Capitoline Hill in Rome was the
original Capitol.
Capitalization. When it does not apply
to investment and the financial kind
of capital, the term capitalization concerns
the use of capital letters in writing
and printing.
Which words start with capitals (upper-case
letters) and which start with
small letters (lower-case letters) has been
decided by custom in most instances, although
differences on many points exist.
Questions can often be resolved by a dictionary.
(But some dictionaries are not
helpful. The otherwise authoritative Oxford
English Dictionary capitalizes all
entries. Webster’s Third capitalizes almost
none, running such entries as
“kansas city” and “saint patrick’s day”
while noting that they are “usu cap”;
when are they not? The capitalization
scheme for entry titles in our book is described
under General Topics, near the
front.)
Sometimes one’s personal preference
decides, although in the interest of readers,
it ought not to be followed to an extreme.
At one extreme is the shunning of
all capitals, a quirk of two literary personages
of the past; at another is the arbitrary
capitalization of words for
emphasis, which was common centuries
back. A condensed excerpt from the
Declaration of Independence follows.
The first letter of every noun deemed important
is a capital.
. . . All men are created equal . . . with
certain unalienable Rights, that
among these are Life, Liberty and the
pursuit of Happiness.—That to secure
these rights, Governments are instituted
among Men, deriving their just
powers from the consent of the governed,—That
whenever any Form of
Government becomes destructive of
these ends, it is the Right of the
People . . . to institute new Government
. . . to effect their Safety and
Happiness.
Some current principles of capitalization
follow.
1. Beginning of a sentence. The first
letter of every sentence starts with a capital.
So does a sentence fragment that
stands alone. “Her answer was brief.
‘Yes.’ ”
2. Colon. A sentence fragment following
a colon is not usually capitalized:
“I’m eating only three times a day:
morning, noon, and night.” Whether to
capitalize a complete sentence after a
colon is up to each writer or publication.
3. Days, times of the year. Days,
months, and holidays are capitalized:
Thursday, November, Thanksgiving.
Seasons are usually not: winter, summer.
4. Derivatives of names. Most adjectives
derived from people’s names or
other proper nouns are capitalized: Euclidean
geometry, Georgian architecture,
Shakespearean plays, Machiavellian
ethics, Roman numerals. Many are not:
pasteurized milk, roman type, italic type,
french fries, venetian blinds.
5. Heavenly bodies. They are usually
capital: Saturn, Milky Way, the star Sirius.
The Earth and the Sun may be capital
in the context of astronomy, small in
general contexts: the greatest show on
earth; soaking up the sun.
6. Historical events and eras. They are
often capitalized: The Industrial Revolution.
World War II. But there is disagreement;
it is “the battle of Hastings” in
one work, “The Battle of Hastings” in
another.
7. Initialisms and acronyms. Most initialisms
and acronyms, such as M.D.
and AIDS, are all capitals. Doctor of philosophy
becomes Ph.D. Abbreviations,
like com. for committee and secry. for
secretary, do not need capitalizing.