TL; DR: Cuíña < Colina is a sure thing, but I'm not sure of the meaning of the Medieval word or words
colina. Certainly it's more interesting than what I was expecting
Well, the multi-volume "Diccionario crítico etimológico castellano e hispánico" is the place to go for the etymology of a Spanish or a Galician word. It was a great achievement, even more so when considering that Joan Coromines was an exile for a part of his life (thanks Franco; never again Franco; bye-bye Franco); but it is also as far as you can go without computers.
Also, most of the medieval Galician charters and documents, either in Latin or in Galician, that we can access now in the web (
CODOLGA,
GMH,
Corpux Xelmirez and other corpora) have been edited and published during the last twenty or thirty years, so Coromines had no access to this material, which means that sometimes he made wrong assessments in reference to a given word. An example: he considered that the family of the word
marco,
marcar,
demarcar…was a Germanism that came to Spanish from Italian… But in fact in Galician these are very common daily words which are well presents in local documents since the 9th century (we don't have many earlier documents), so they happen to be local Germanisms probably taken from the Suebi who settled here in the 5th century (as
brétema,
laverca,
groba,
meixengra,
zapa, to cite some usual suspects).
So I guess that Coromines was not even aware of the presence of this word,
colina, in Latin local documents.
As for its meaning, I'm not sure at all; most of the time is already a place name, any of today's Cuíña/Cuíñas. Examples:
“In Caldelas et Tibros
Colinas et tercia parte de Baselisco. Sub urbe lucense Rapati. In nave fracta Eclesia Alba cum Agra Mala et pumares de Presares. In Bragantinos villa de Alio cum insula de Calion. In Celtigos de Reilon, et sexta de Pinario integra in Carnota. In Morracio Bellucio cum pumare de Mauron, et terras et pumares de Gienesto” 934
“alias adiunctiones nominatas -id sunt- Uilla Mediana.
Colina cum familia sua. Argondi. Belsari.” 1071 ( → now Cuíña, Saa, Lugo, next to the villages called Argonde and Belesar)
It ins't easy, also, to get to the meaning of this word when used as an appellative. I would say that it refers to a vegetable garden or a seedbed, and in that case they are clearly related to Modern Galician
coíña 'cabbage seed/sprout' < *colina ← Latin caulis; rather than to Latin collinus:
“de ipsa tercia vendimus vobis inde medietatem integra vinea, pumares, ceresales, perales, ipsa
colina medietate, et de ipso lagare de tercia medietate integra, et de ipso agro per ubi est conclauso tercia media integra et de ipsa carrale tercia media ipsa vinea que comparavimus de Tanoi medietate integra” 885 (
ipsa colina medietate: maybe here
colina is a cabbage garden?)
“Et alia vinea ad casa de Gundemaro, levat se de illa
colina et vai per succo de Daniel ipsa vinea cum suo conclauso” 975
In any case,
cuíña today is just barely and locally attested as an appellative, meaning 'little hill'; while
coíña is 'cabbage sprout'.
Edit: grammar, readability