Answer:

san

Answer	Crossword Clue
SAN	... Andreas fault
SAN	Japanese honorific
SAN	... Jose

SAN	Hokkaido honorific
SAN	... Salvador
SAN	Start of many Mexican city names
SAN	... Luis Obispo
SAN	... Juan
SAN	... Joaquin Valley
SAN	First word of many California city names
SAN	Lead-in to Francisco or Pedro

SAN	Part of U.C.S.F.
SAN	... Marino
SAN	... Gabriel Mountains
SAN	Title of politeness
SAN	... Diego
SAN	Lead-in to Pablo or Carlos
SAN	... Gabriel
SAN	Part of S.F.

SAN	... Andreas Fault
SAN	What three of California's four largest cities share
SAN	Introduction for Pedro or Diego?
SAN	Word in many California city names
SAN	Honshu honorific
SAN	... Francisco
SAN	Something Pedro and Pablo might have?
SAN	Gabriel or Giorgio

SAN	Start of the names of three of the 10 most populous U.S. cities
SAN	... Pedro
SAN	Puccini's Cio-Cio-...
SAN	Part of S.F.S.U.
SAN	Japanese surname follower
SAN	... Bernardino Mountains
SAN	Angelo or Antonio
SAN	California city name starter

SAN	Antonio or Joaquin
SAN	Colorado's ... Luis Peak
SAN	... Fernando Valley
SAN	Start of many Latin American city names
SAN	... Clemente