Section 117G. As used in sections one hundred and seventeen G to one hundred and seventeen L, inclusive, the following words and phrases shall have the following meanings:—

”Grade” or ”grades” shall mean the standards for potatoes established and promulgated by the commissioner of food and agriculture as herein provided as the official grades of potatoes for Massachusetts.

”Plainly and conspicuously” shall mean that the lettering used to furnish information required by law on containers shall be legible enough so as not to be obscured by other markings or illustrations used thereon. Printing or stamped terms shall be not less than three eighths of an inch in height.