The word Hebrew can refer to the language or people but in the Hebrew language, the Hebrew language is called "eevriyt", a Hebrew person is called an "eevriy" (singular) and the Hebrew people are called "eevriym" (plural). All of these words come from the root "avar" meaning "to cross over." One of Abraham's descendents was Eber (pronounced "ever" in Hebrew) and the descendents of Eber/Ever are called eevriym (the plural form of the name Eber/Ever). So, Abraham is an eevriy, one descended from Eber. You will also notice that in English we say "Hebrew" which is supposed to be a transliteration of "eevriy," but where did the "H" come from as there is no "H" in eevriy? Most likely, the name Hebrew is derived from the people called the Habiru who may or may not be the Hebrews of the Bible.