GRUB, the larva of an insect, a caterpillar, maggot. The word is formed from the verb " to grub," to dig, break up the surface of the ground, and clear of stumps, roots, weeds, etc. According to the New English Dictionary, " grub " may be referred to an ablaut variant of the Old Teutonic grab-, to dig, cf. " grave." Skeat (Etym. Diet. 1898) refers it rather to the root seen in " grope," " grab," etc., the original meaning " to search for." The earliest quotation of the slang use of the word in the sense of food in the New English Dictionary is dated 1659 from Ancient Poems, Ballads, etc., Percy Society Publications. " Grubstreet," as a collective term for needy hack-writers, dates from the 17th century and is due to the name of a street near Moorfields, London, now Milton Street, which was as Johnson says " much inhabited by writers of small histories, dictionaries and temporary poems."
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)