by-name n.

Old English be- (unstressed) or bi (stressed) "near, in, by, during, about," from Proto-Germanic *bi "around, about," in compounds often merely intensive (source also of Old Saxon and Old Frisian bi "by, near," Middle Dutch bie, Dutch bij, German bei "by, at, near," Gothic bi "about"), from PIE *bhi, reduced form of root *ambhi- "around."

As an adverb by c. 1300, "near, close at hand."

OED (2nd ed. print) has 38 distinct definitions of it as a preposition. Originally an adverbial particle of place, which sense survives in place names (Whitby, Grimsby, etc., also compare rudesby). Elliptical use for "secondary course" was in Old English (opposed to main, as in byway, also compare by-blow "illegitimate child," 1590s, Middle English loteby "a concubine," from obsolete lote "to lurk, lie hidden"). This also is the sense of the second by in the phrase by the by (1610s).

By the way literally means "along the way" (c. 1200), hence "in passing by," used figuratively to introduce a tangential observation ("incidentally") by 1540s. To swear by something or someone is in Old English, perhaps originally "in the presence of." Phrase by and by (early 14c.) originally meant "one by one," with by apparently denoting succession; modern sense of "before long" is from 1520s.

By and large "in all its length and breadth" (1660s) originally was nautical, "sailing to the wind and off it," hence "in one direction then another;" from nautical expression large wind, one that crosses the ship's line in a favorable direction.

"word by which a person or thing is denoted," Old English nama, noma "name, reputation," from Proto-Germanic *naman- (source also of Old Saxon namo, Old Frisian nama, Old High German namo, German Name, Middle Dutch name, Dutch naam, Old Norse nafn, Gothic namo "name"), from PIE root *no-men- "name."

Meaning "a famous person" is from 1610s (man of name "man of distinction" is from c. 1400). Meaning "one's reputation, that which is commonly said of a person" is from c. 1300. As a modifier meaning "well-known," it is attested by 1938.

In the name of "in behalf of, by authority of," used in invocations, etc., is by late 14c. Name-day "the day sacred to the saint whose name a person bears" is by 1721. Name brand "product made by a well-known company" is from 1944. Name-dropper "person who seeks to impress others by mentioning well-known persons in a familiar way" is by 1947. Name-child, one named out of regard for another, is attested by 1830. The name of the game "the essential thing or quality" is from 1966; to have one's name in lights "be a famous performer" is by 1908.

"I don't realize yet how fortunate I am. It seems that I have been dreaming. When I see my name in lights in front of the theatre, I think, 'No. It isn't I.' " [Billie Burke interview in "The Theatre Magazine," Nov. 1908]