Numerals are often used in numeronyms: in combination with other numerals and with letters to represent a word, phrase, or concept. This post loosens the definition of numeronym to also include a numeral without one or more accompanying letters and with or without other symbols.
Ordinal numbers can represent something, as when we speak, for example, of a “third” in reference to an additional person who joins two people or when we refer, for example, to “the 25th” to denote a certain day of the month, but the following terms, which include cardinal numbers, represent more than the sum of their parts, too.
The number 101, used in combination with a word representing a topic, is used to imply that a piece of knowledge under discussion is elementary, as if it were equivalent to the content of an introductory college course. (Such courses are often numbered 101 in a three-digit designation system.) For example, the principle of supply and demand might be said to be “Economics 101,” meaning it is easy to understand.
A 180 is a half turn and a 360 is a full turn, representing the number of degrees in a circle; numbers larger than 360 may appear in reference to sports such as skating or diving in which participants may turn more than one full revolution; 180 may also refer figuratively to someone reversing one’s position on an issue.
The abbreviations WWI and WWII stand for “World War I” and “World War II” (and there is also the hypothetical World War III, or WWIII); they are sometimes represented with Arabic numerals, though Roman numerals are the conventional treatment.
Y2K is an abbreviation for “year 2000,” pertaining to the (largely unfounded) concern late in the twentieth century that a fundamental programming flaw would, at the turn of the century, cause catastrophic breakdowns in information processing, leading to serious repercussions throughout the civilized world. Another term stemming from business is 24/7, referring to the number of hours in a day and the number of days in a week to denote incessant attention to something. (The term is also extended to 24/7/365 to refer to the number of days in the year as well.)
Guns are often referred to simply by their caliber: for example, .22, .357, and .45 refer to the diameter of the bullets used in a particular firearm.
3D is an abbreviation for “three-dimensional,” pertaining to images and films with this feature. Abbreviations for television programs include TW3 for That Was the Week That Was, a satirical comedy program on the United Kingdom’s BBC network during the early 1960s, and MST3K for Mystery Science Theater 3000, a late-twentieth-century American program that poked fun at mediocre low-budget films. Meanwhile W3 is an abbreviation for “World Wide Web,” which is now generally abbreviated to web.
To get the 411 on something is to obtain information; 411 is the telephone number for directory assistance, which provides phone numbers for people who want to contact a person or an organization but do not have the entity’s number. (This number is sometimes styled 4-1-1.) Telephone area codes are often employed as shorthand to refer to geographical regions, as in the use of “the 415” to represent San Francisco and its environs.
401(k) refers to a specific pension account defined in that section of the Internal Revenue Service tax code. Similarly, a tax-exempt nonprofit organization is referred to as a 501(c)(3), a label that pertains to the corresponding section of the IRS tax code.
5K, 10K, and so on are abbreviations referring to footraces of 5,000 and 10,000 meters, respectively, as well as longer events; K stands for kilo-, a prefix meaning “one thousand.” Shorter races held on tracks (and swim events) may be called, for example, “the 400,” referring to a 400-meter dash or another race of that length.
Text-speak takes advantage of numeronyms to reduce the number of characters necessary to express a word: Gr8, for example, represents great, and l8r is equivalent to later. Related usage includes computer terms that are abbreviated, for example, from localization to l10n. (The numeronym consists of the first and last letters of the word interrupted by a number representing how many intervening letters are missing.)
A similar system is leetspeak (leet derives from elite to acknowledge that those who know the system are privileged to do so in comparison to the ignorant masses), in which numerals replace similarly shaped letters, such as in n00b, which represents a misspelling and abbreviation of newbie (meaning “novice”).
G8 and G20 refer to international political forums consisting of the respective number of participant nations; G stands for group in designations such as “Group of 8.”
K9 is an abbreviation for canine because it is pronounced the same as the word for dogs and other doglike animals; it is employed in the context of dogs used in law enforcement.
Also pertaining to law enforcement is the ten-code, a system of numerical codes beginning with 10 that represent words and ideas; the most familiar to laypeople is 10-4, meaning “understood.”