numerology (n.)

c. 1300, "sum, aggregate of a collection," from Anglo-French noumbre, Old French nombre and directly from Latin numerus "a number, quantity," from PIE root *nem- "assign, allot; take."

The meaning "written symbol or figure of arithmetic value" is from late 14c. The meaning "single (numbered) issue of a magazine" is from 1795. The colloquial sense of "a person or thing" is by 1894. The meaning "dialing combination to reach a particular telephone receiver" is from 1879; hence wrong number (1886).

The sense of "musical selection" (1885) is from popular theater programs, where acts were marked by a number. Earlier numbers meant "metrical sound or utterance, measured or harmonic expression" (late 15c.) and, from 1580s, "poetical measure, poetry, verse."

Number one "oneself" is from 1704 (mock-Italian form numero uno attested from 1973); the biblical Book of Numbers (c. 1400, Latin Numeri, Greek Arithmoi) is so called because it begins with a census of the Israelites. Childish slang number one and number two for "urination" and "defecation" attested from 1902. Number cruncher is 1966, of machines; 1971 of persons.

To get or have (someone's) number "have someone figured out" is attested from 1853; to say one's number is up (1806) meaning "one's time has come" is a reference to the numbers on a lottery, draft, etc. The numbers "illegal lottery" is from 1897, American English. Do a number on is by 1969, exact meaning unclear; by the early 1970s it can mean "emotionally manipulate" (1970), "damage or injure" (1975), or "assassinate, kill" (1971). The 1972 book of gay slang The Queen's Vernacular says it is synonymous with game, as well as with trick in the prostitution and magical senses, and defines it as "one’s skit, act, schtick; contrived actions used to gain attention." The image may be of a routine song-and-dance performance, which if so makes it from the "musical selection" sense.

word-forming element meaning "a speaking, discourse, treatise, doctrine, theory, science," from Medieval Latin -logia, French -logie, and directly from Greek -logia, from -log-, combining form of legein "to speak, tell;" thus, "the character or deportment of one who speaks or treats of (a certain subject);" from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')."

In philology "love of learning; love of words or discourse," apology, doxology, analogy, trilogy, eulogy, etc., Greek logos "word, speech, statement, discourse" is directly concerned.

Proto-Indo-European root meaning "assign, allot; take."

It forms all or part of: agronomy; anomie; anomy; antinomian; antinomy; astronomer; astronomy; autonomous; autonomy; benumb; Deuteronomy; economy; enumerate; enumeration; gastronomy; heteronomy; innumerable; metronome; namaste; nemesis; nimble; nim; nomad; nomothetic; numb; numeracy; numeral; numerator; numerical; numerology; numerous; numismatic; supernumerary; taxonomy.

It is the hypothetical source of/evidence for its existence is provided by: Greek nemein "to deal out," nemesis "just indignation;" Latin numerus "number;" Lithuanian nuoma "rent, interest;" Middle Irish nos "custom, usage;" German nehmen "to take."