Page "Genesis Rabbah" Paragraph 13

The work may have received its name, " Genesis Rabbah ," from that larger midrash at the beginning of Genesis, unless that designation was originally used to distinguish this midrash from the shorter and older one, which was ascribed to Rabbi Hoshayah.

The opinion that the name of the midrash finds its explanation in the first words, " Rabbi Hosha ' yah rabbah began.

" as if the word " rabbah " belonged originally to the name of the amora, and that the name of the work, " Genesis Rabba ," is an abbreviation of " Bereshit derabbi Hoshayah rabbah ," is untenable for the reason that in the best manuscripts — and in a very old quotation — the name " Rabbi Hoshayah " stands without the addition " rabbah " in the first preface at the beginning of the midrash.

It would be singular if the authorial designation had been lost and yet the attribute had remained in the title of the midrash.