Gypsum Alley is listed in an 1881 city ordinance establishing the names of all streets in Pittsburgh. It became Gypsum Way in 1914, when another ordinance changed all alleys in the city to ways.
Bob Regan includes "Gypsum" in his "Streets of Pittsburgh" crossword puzzle, clued as "Soft, white mineral composed of hydrous sulfate of lime, used as plaster of Paris. Unfortunately this is just a dictionary definition of the word gypsum and gives no information about the origin of the name.
- "An ordinance establishing the names of avenues, streets, lanes and alleys of the City of Pittsburgh." Pittsburgh city ordinance, 1881, no. 33. Passed Feb. 28, 1881; approved Mar. 4, 1881. Ordinance Book 5, p. 212. In Municipal Record: Minutes of the proceedings of the Select and Common Councils of the City of Pittsburgh, for the year 1880, pp. 213–234, Herald Printing Co., Pittsburgh, 1881 (Internet Archive pghmunicipalrecord1880). [view source] ordinance-1881-33
- "An ordinance changing the name 'Alley' on every thoroughfare in the City of Pittsburgh, to 'Way.'" Pittsburgh city ordinance, 1914, no. 402. Passed Nov. 10, 1914; approved Nov. 16, 1914. Ordinance Book 26, p. 360. Reprinted in the Pittsburgh Post, Nov. 23, 1914, p. 11 (Newspapers.com 86505785), and Nov. 24, p. 12 (Newspapers.com 86505809). [view source] ordinance-1914-402
- Bob Regan. The Names of Pittsburgh: How the city, neighborhoods, streets, parks and more got their names, pp. 183, 186. The Local History Company, Pittsburgh, 2009, ISBN 978-0-9770429-7-5. [view source] regan