The Claremont Coptic encyclopedia is an “updated and continuously expanding and evolving web-based version of the Coptic Encyclopedia,” an exemplary multi-volume work published in 1991 (editor: Aziz Atiya), significantly ahead of similar resources in Syriac and Ethiopic Christianity. It is now available in an open-access web version, where individual articles can be searched according to creator and subject (content tags, not necessarily article title); currently, the website currently consists entirely of reproductions from the 1991 edition, but promises expansion in the years ahead.
http://ccdl.libraries.claremont.edu/cdm/landingpage/collection/cce