The davoch, davach or is an ancient Scottish land measurement. All of these terms are cognate with modern Scottish Gaelic . The word dabh or means an "ox" (cf. oxgang, damh-imir), but dabhach can also refer to a "tub", so may indicate productivity. It was called the arachor in the Lennox.
It is thought that the measurement is of Pictish origins, and is most common in the north east, and often absent in the south of Scotland. It is particularly common in various placenames to this day, often in the form "Daugh of Invermarkie" etc. The name "Haddo" is also a corruption of “Hauf Daugh”, or half-davoch, in turn a translation of “leth-dhabhach”.
Scottish land measurements tended to be based on how much they could support. This was particularly important in a country where fertility would vary widely. In the east a davoch would be a portion of land that could support 60 cattle or oxen. MacBain reckoned the davoch to be “either one or four ploughgates, according to locality and land”. A ploughgate contains about 100 Scots acres (5.3 km2).
Watson, in The Placenames of Ross & Cromarty, says, “usually four ploughgates”. Skene in Celtic Scotland says:
The pennyland is thought to be of Norse origin, so it is possible that Norse and native systems were conflated in the west.
Prof. MacKinnon in Place and Personal Names of Argyll says,
The lexicographer Jamieson claimed that a daugh was enough to produce about 48 bolls, and averaged an area of approximately 1 1⁄2 square miles (3.9 km2).
Daughs are referred to in the Book of Deer, and were recorded as being in use in the late 18th century in Inverness-shire. In some areas, a quarter of a davoch was a ploughgate, and an eighth an ochdamh.