Common version of a line from Gertrude Stein -- the sentence first seen in the poem "Sacred Emily", written 1913, is actually "Rose is a rose is a rose is a rose." But she re-used the line in several other places with different numbers of repetitions of "rose" and with or without the article "A" at the beginning, so there can't be said to be only one correct quotation. "A rose is a rose is a rose" is the most-seen version when people quote Stein.

So what's it supposed to mean? Her answer when asked about it was 'that in the time of Homer, or of Chaucer, when the language was new, "the poet could use the name of the thing and the thing was really there." But as memory took it over, it lost its identity, which she was trying to recover.' She also said in Four in America that "I think in that line the rose is red for the first time in English poetry for a hundred years." My "American Literature 1900-1945" professor said that the line is supposed to have come to Stein in a dream, but I cannot find any confirmation of this.

Source:
http://www.csustan.edu/english/reuben/pal/chap7/stein.html http://www.english.uiuc.edu/finnegan/English%20256/gertrude_stein.htm