The nave of a wheel; a boss; also a skid. (Welsh, hob, a swelling, a protuberance; compare also a hwb.) The Americans call Boston, Massachusetts, “The hub [boss] of the solar system.”
“Boston State-house is the hub of the solar system.” —
“Calcutta swaggers as if it were the hub of the universe.” —Daily News, 1886.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894