What De, Von, Van, O' and Mac Are Actually Claiming

De Gaulle. Von Trapp. O'Brien. MacDonald. Van Dijk.

Every one of those little words is making a claim, and the claims fall into two groups. Some tell you about a place. Some tell you about a father. Knowing which one you are looking at tells you what kind of surname it is.

The place group

De is French and means of. It attached a person to an estate, so de Gaulle originally meant of Gaulle, referring to a landholding rather than a family. The same particle runs through Spanish, Portuguese and Italian, where de, da, di, del and della all do the same job with local grammar. Not every de marks nobility, and in Spain and Italy plenty of ordinary families carry one, which is a common source of confusion.

Von is German and also means of or from. In German and Austrian usage it was a reliable marker of nobility for a long stretch of history, more so than French de ever was, because the German states regulated its use. Austria abolished nobiliary particles outright in 1919, which is why Austrian descendants of noble families dropped the von and German ones did not.

Van is Dutch and means of or from, and here the association reverses. Dutch van almost never indicates nobility. It usually points at a geographic feature or a place of origin, so van Dijk is of the dyke and van den Berg is of the mountain. Dutch has a whole category for these particles, the tussenvoegsel, and Dutch alphabetisation ignores them, filing van Dijk under D.

Ski does the same work at the other end of the word. In Polish, an estate at Bielsk produced the surname Bielski, which is a suffix doing what de and von do as prefixes.

The parentage group

Mac is Gaelic for son of, used across Ireland and Scotland. MacDonald is the son of Donald. Mc is the same word abbreviated, and the notion that Mc is Irish while Mac is Scottish is folklore rather than orthography. Both appear in both countries, and the spelling usually reflects a clerk's preference.

O' is Irish and means grandson of or descendant of, which places it one generation further back than Mac. O'Brien claims descent from Brian, and the apostrophe is an English addition standing in for the Irish Ó. Murphy comes from Ó Murchadha and lost its prefix entirely during anglicisation, which happened to a very large number of Irish names.

Fitz is Norman French from Latin filius, son. It arrived in Ireland with the Anglo-Norman invasion, so Fitzgerald means son of Gerald. It also acquired a secondary use for acknowledged royal illegitimate children, which is where FitzRoy, son of the king, comes from.

Ap is Welsh for son of, and it explains a set of English surnames that look unrelated to it. Ap Rhys collapsed into Price, ap Hywel into Powell, ap Owen into Bowen. The prefix survives as the first letter of the modern name.

Why the distinction matters

A place prefix tells you where a family was. A parentage prefix tells you who they descended from, which means it was once a name that changed every generation before it froze.

Iceland never let its patronymics freeze and still rebuilds them for every child, which is what all the Mac and Ó names were doing before hereditary surnames locked them in place. Every MacDonald is carrying a snapshot of one specific father-son relationship that stopped updating several centuries ago.

What happened to them in transit

Prefixes take damage when they cross borders. English-language paperwork has never known what to do with a name in two parts, so Van Der Berg becomes Vanderberg, de la Cruz becomes Delacruz, and O'Neill loses the apostrophe.

Irish names suffered the most. British administration in Ireland stripped Ó and Mac from names on a large scale, and a partial restoration happened during the Gaelic revival, which is why the apostrophe is present in some branches of a family and absent in others.