Gillum
Gillum is usually an English surname that began as a form of the personal name William, or less often as a related nickname-based variant.
The #6,676 most common surname in the United States (2010 Census) — about 1 in every 61,017 Americans shares it.
Etymology
Gillum is generally understood as a variant surname built from the medieval given name William, which entered English through Norman French. In surname formation, short and reduced forms of William produced many spellings and pet forms, and Gillum fits into that broader pattern. In some cases, surnames of this shape may also reflect regional pronunciation or spelling variation rather than a separate original name.
History
The name appears to belong to the wide family of English surnames that grew out of William, one of the most common medieval personal names in England. Over time, local speech and clerical spelling produced many forms, some quite different on the page but close in sound. Gillum is now comparatively uncommon, but it survives in English-speaking countries, especially the United States.
Origin
Regions
Variant spellings
Fun fact
Many surnames that look unrelated on paper are actually old sound-shifted forms of William, and Gillum is likely one of them.