Sigma Sigma Omicron was a national collegiate sorority operating in the United States from November 1, 1920 to 1933. The Alpha chapter was chartered at New York University. In July 1927, the sorority changed its name to Sigma Phi Beta. The sorority was absorbed by Phi Omega Pi.
According to the 1931 edition of The Sorority Handbook, there were 10 chapters with 1,000 members (p. 79).
Read more about Sigma Sigma Omicron: Insignia and Traditions, Tewanah