Recorded in many spellings including Lomas, Lomaz, Lumox, Lummus, Lummis and Loomis, this is an English surname. It is locational from a former village called Lomax, a now "lost" place originally near the town of Bury, in the county of Lancashire. Recorded in the Middle Ages as Lumhalghs, the component elements of the placename are believed to be the pre 7th century Old English word "lumm", meaning a pool, and reflected in the dialectal term "lum" denoting a well, plus "halh", a nook or recess.

It is estimated that at least three thousand villages and hamlets have disappeared from the maps in Britain in the past five centuries. The prime cause for these "disappearances" was the enforced clearing of land and the dispersal of the former inhabitants, to make way for sheep pastures at the height of the wool trade in the 17th Century, along with natural causes such as the Black Death of 1348.

Early examples of the surname recordings taken from surviving church registers of the county of Lancashire include those of Elizabeth Lomas, who was christened at Farnworth near Prescot on November 8th 1549, whilst on January 13th 1562, Alice Lomax and Roger Wroe were married at Middleton by Oldham. A coat of Arms granted to the family depicts three black fleurs-de-lis between two red palets on a silver shield. Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as the Poll Tax