真的運出黃金的那段西非海岸
這一支是名字的原點：海岸上的「金」是真的金屬，而不是比喻。從這條海岸，名字先變成殖民地的名字，最後才被國家獨立換掉。
noun · B2
The former name of Ghana. It was the name of the British colony in West Africa, and it stopped being used when the country became independent in 1957.
黃金海岸（迦納舊稱）
核心畫面
Every use of this name puts the same two things side by side: a line of coast, and gold. Stand on that shore and something valuable is moving — in the oldest use, metal going out on ships; in the newer ones, money sitting still in the houses behind the beach. The coast is always the edge where the value gathers, which is why the name keeps being handed to new places.
這個名字的每一種用法，都把同樣兩樣東西放在一起：一段海岸，還有「金」。站在那條海岸線上，總有值錢的東西在那裡——最早…更多收起
這個名字的每一種用法，都把同樣兩樣東西放在一起：一段海岸，還有「金」。站在那條海岸線上，總有值錢的東西在那裡——最早是金屬被裝上船運出去，後來是錢安安穩穩地留在沙灘後面的房子裡。海岸一直是價值聚集的那條邊，所以這個名字才會一再被拿去命名新的地方。From the word’s history
Wiktionary records that the West African name is a calque of Portuguese Costa do Ouro, given because gold from Ghana's Ashanti Region was shipped out along that coast. It also records that the Australian name began as an informal change to the region's earlier name, South Coast, because prices there were relatively high in the 1940s and 1950s.
詞源資料指出，西非那個名字是葡萄牙語 Costa do Ouro 的直譯，因為迦納阿散蒂地區的黃金從這段海岸運出。同一份資料也記載，澳洲的用法一開始只是把舊名 South Coast 半開玩笑地改掉，原因是 1940、50 年代那裡物價偏高。所以「金」在前者指真正的金屬，在後者指價格。
Wiktionary, entry “Gold Coast” (etymology_text supplied in the evidence packet; kaikki source_ref 3f6f69a190036ae4:1551169991)
Two branches
「金」改指價錢的那些海岸
同樣是一段海岸加上「金」，但這裡的金不是礦產，而是價格。海岸還是價值聚集的那條邊，只是值錢的東西換成了房子和租金。
noun · B2
In American English, the expensive part of a city or town where large, comfortable homes stand, especially along a lake or the sea.
高級住宅區（水岸）