Raphael Lemkin, who coined the term genocide, himself referred to Armenian Genocide at that time.
Armenian Genocide cannot be disputed as a legal term, as it fully satisfies universally accepted term Genocide codified in UN 1948 Convention Article 2: hrweb.org/legal/genocide.html
and there are a lot of documents, as well as Turkish confirming this Fact: genocide-museum.am/eng/turkish.php
This video is part of a panel discussion on the U.N. Genocide Convention, broadcasted by CBS (as part of its 'U.N. Casebook' documentary series) within 'U.N. Casebook, Chapter XXI, Genocide' on February 13, 1949.
Source for it: youtube.com/watch?v=CXliPhsI530&feature=youtu.be&t=405
'Interview' with Lemkin - 23:47-27:19
This short video has been referred in "The Armenian Genocide", documentary made by Two Cats production and televised by American PBS in 2006.