This is a very old Lancashire locational name, which derives from the Village of Dilworth, near Ribchester in Lancashire. The medieval spelling of the name of the village may have been Dylleword, although this is not directly recorded in the name spelling. The origin is Olde English pre 7th Century. The name meaning "the enclosure (word) in which the dill (herb) grows. Locational names were almost always given when a person moved to another village or to the Lord of the Manor, as in the first recording. In 1562, one Ewan Dilworth was recorded as being a member of the prestan Guild. The first recorded spelling of the family name is shown to be that of William de Dilleworth. which was dated 1332, Ribchester, Lancashire. during the reign of King Edward III, The Father of the Navy, 1327 - 1377. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.