Lexicology is the study of the origin and meaning of words; lexicography is the practice of dictionary making. Lexicology is a theoretical science; lexicography, an applied science. Good dictionary makers, however, inevitably are both lexicologists and lexicographers; together the two sciences form the branch of LINGUISTICS that links the abstract discipline SEMANTICS and the tangible artifact the DICTIONARY.
The dictionary maker must first decide what vocabulary entries to include. Then each word's spelling (including capitalization), pronunciation, part of speech, inflection (if any), etymology, and meaning must be ascertained. Viewed narrowly, lexicology concerns itself only with the last two topics, etymology and meaning; all seven are nonetheless inextricably related. Spelling and pronunciation, for example, give vital clues about a word's origin; and most words take on different meanings when they serve as different parts of speech--the noun light, for instance, must be defined quite differently from the adjective.
The central question confronting the lexicographer is how prescriptive a dictionary should be. Should a dictionary record the language as it is spoken or as it "ought" to be spoken? Should a dictionary describe or prescribe? Many people turn to a dictionary to find out if a word or definition exists; others want to know only if a spelling, pronunciation, or meaning is considered correct.
Whenever the two elements story and writer are pronounced with equal stress, the collocation storywriter is felt as two words. When, however, it is pronounced as storyteller, with reduced or secondary stress on the third syllable, storywriter becomes one word. Compare, for example, the difference in stress given to house in the sentences That is the white house I was telling you about and That is the White House. In the second sentence White House is pronounced almost as if it were one word.
Similarly, take it or leave it can function either as a phrase--as in, You can take it or leave it--or, with a more rushed and slurred pronunciation, as a word. The collocation occurs so infrequently as a word, however, and when it does it has so distinctly the ring of an expression coined for an occasion, that lexicographers generally choose to ignore it.
The two n's of millennium and the -um ending of memorandum are certified by the Latin sources of the words. Memorandum is the neuter form of the Latin gerundive memorandus, and millennium combines Latin mille, "thousand," with an ending derived from the word, annus, for year. Many other so-called correct English spellings, however, are incorrect from a Latin point of view. For instance, the British use the spelling centre for the word derived from Latin centrum, but ever since Noah Webster's time, Americans have been writing center.
Inflections (the changes in forms of words) provide one of the most important indications of a word's part of speech. Some linguists even classify words strictly according to the inflections they take. Verbs, for example, may be defined as those words that can have the inflection -ing for the present participle or -ed for the past tense and past participle.
A word may be borrowed more than once from another language. French salon, for instance, gave rise to both English salon, a formal receiving room, and saloon, an informal drinking establishment. Sometimes loanwords change so much in meaning that only spelling or pronunciation can give any clue to their origin. The French word nice, for instance, from Latin nescius, "not knowing," meant "foolish" when it was first adopted into English during the 13th century. By the second half of the 16th century, however, it had come to mean "fastidious"--having passed through the intermediate meanings "wanton" (14th century), "strange" or "uncommon" (15th century), and "coy" and "shy" (16th century).
Definitions may be listed either chronologically or in order of popularity. That is, the definitions may proceed either from the first meaning that a word had in the language to the most recent, or from the most common meaning to the least common. Under the entry nice, for example, a historical dictionary might begin with "foolish"--which is what nice meant when it was first used in English in the 13th century--and end with "agreeable"; another dictionary, however, will place "agreeable" first--since that is currently the word's most prevalent sense--and then list the other meanings in descending order of popularity.
Placing a word's etymology before its definitions enables the reader to see quickly where the first meaning of the word came from. The English word curious, for instance, derives from Old French curios, which in turn descends from Latin curiousus, "careful." Thus the origin of the first sense--"solicitous"--borne by the word curious in English becomes immediately apparent.
Many people, however, want to know what the most common current meaning of a word is, and they expect to find that meaning given first. In that case, information about a word's origin can get in the way or even be misleading. In recognition of this fact, some dictionaries now place the etymology at the end of each entry, after the definitions.