Sidney Wood, in a comment on my last post, brought up the matter of the Cornish place-name element rose. He is quite right to point out that this has nothing to with flowers in the vast majority of Cornish place-names. The element ros is a bit of a problem, because it has two possible meanings: (1) rough land/heath (2) promontory. Unfortunately, names containing rose can also be corruptions of original names which contained res, which means “ford/watercourse”. Of the 50 names beginning Ros(e) in Weatherhill C.(2009) A Concise Dictionary of Cornish Place-Names, Cathair na Mart: Evertype 20% appear to derive from res originals, 30% are glossed as meaning promontory and the remaining 50% as meaning rough land.
Sidney also asks about the <d> in the name Culdrose. I have been unable so far to find any explanation of this. There certainly is no commonly occurring mutation that could explain this. The name is a puzzle anyway, because in Cornish, as in all Celtic languages, the vast majority of adjectives follow the noun, but in Culdrose the adjective kul (Kernewek Kemmyn spelling) it precedes. There is a short list of adjectives which regularly precede, but kul doesn’t figure in it.
Sidney’s other question concerns the surname Pengrowse. On the face of it this looks like a toponym meaning “headland with a cross” from Cornish pen + crows with a regular k → ɡ initial mutation of the second element. I know of no common phonological process which could derive this from the name Penrose, which is what Sidney asks about.
Photo credit: Atoma. Used under this licence.