BIG RIVER

I recently was surprised to learn that the island of Guadalcanal, best known for a major WWII battle, is named after a city in Spain. Apparently it was discovered in 1568 by Spanish explorer Álvaro de Mendaña de Neira, who was reminded of his hometown. That comes from the Arabic phrase wadi al-kabir, meaning "big river". Wadi, which here meant "river" but could also mean "valley" or "riverbed" (and also makes up the first part of toponyms like Guadalajara), comes from the Proto-Semitic root w-d-y, which was generally related to things that protruded. The kabir part comes from the Proto-Semitic root k-b-r, which meant "large", "old", or "great". According to Google Ngrams, literary usage of the name Guadalcanal (unsurprisingly) peaked in 1945, rapidly declined, and has levelled off since.