> How does one differentiate between "donn" translated as a noun meaning
> 'chief or ruler' and the adjective meaning 'brown'?
As you'd imagine, it's no problem in most contexts, since the
adjective "brown" is vastly common, while the noun/adjective
"chief, ruler; princely, noble" is poetic and rare.
It's precisely in personal names such as the ones you mentioned
that the problem arises. As far as I can tell, even the onomastic
experts are often perplexed.
> Examples found tuckedinto proper names include "Lughaidh Iardonn",
> "Donn Bo", "Donngal", "Donnchadh", "Donnacan", "Donn Cuan", etc.
> Would "Iardonn" translate as 'west ruler'?
The element(s) "dunno-/donno-" are found all the way back
in Gaulish personal names as well. Delamarre (DLG) assigns
them separate entries: donno- 'noble' & dunno- 'brun'.
LEIA reports that other scholars (K.-H. Schmidt, Ellis Evans)
do not separate them. One theory is that OI "donn = chief"
and "donn = brown" are originally the very same word, just
as "rúad" can mean either "reddish, brownish red" or "mighty,
formidable" by poetic extension. Vendryes then asks "Cela
tiendrait-il à la couleur du costume distinguant le chef
de sa troupe?" The idea that chiefs wore brown outfits and
thus "donn" also came to mean "chief" is hard for me to
> Does "Donn Bo" translate as 'brown cow' or 'chief cow'?
To mean "brown cow", it ought strictly speaking to be the
compound "donnbó", or else "bó donn". "Donn Bó" as it
stands could mean "Lord of Cows", with "bó" the genitive
As you know, there's a whole slew (< OI 'slúag') of early
figures named "Donn", starting perhaps with the Milesian
who died before setting foot on Ireland's mainland and
may or may not be identical with the "ancestral deity/
god of the dead" of that name. I have no idea if these
guys are all "nobles" or "brown ones".