Dias
A surname most often linked to the Portuguese and Spanish word for “days,” though in some cases it may also be a patronymic or older Iberian name form.
The #2,266 most common surname in the United States (2010 Census) — about 1 in every 19,244 Americans shares it.
Etymology
Dias is best known in Iberian usage, where it can be connected with the word for “days” (Portuguese/Spanish dias), a form ultimately from Latin dies, “day.” In some traditions it is also treated as a surname style that arose as a fixed family name from earlier personal-name usage, rather than as a simple occupational label. Because the same spelling can also appear in different naming systems, its exact origin may vary by family line.
History
The name is common in Portugal, Spain, and across Portuguese-speaking diaspora communities, especially through migration to the Americas. Historical references also show it appearing in older Iberian naming traditions and as part of longer patronymic-style forms. In modern records, Dias is often encountered as a Portuguese surname, but individual family histories may trace it differently.
Origin
Regions
Variant spellings
Fun fact
Because it is short and very old in Iberian usage, Dias can look deceptively simple in records—but the same spelling may belong to different branches with different historical origins.
From the historical record
“in G. ; it leaves its influence either in a new combination or in compensatory lengthening. Thus suain is for supno-s, and see cluain, cuan. G. dias seems from *steip-s-d, W. twys, and vasal may have had an original form like v\j/r)\6'i, Eng. up. (Of. teanga and dingua). In seachd, Lat. septem, the p is…”
— Etymology of the principal Gaelic national names, personal names, surnames