plátano

Plátano is masculine because it derives from Latin "platanus," which was grammatically masculine in Latin and retained that gender when the word entered Spanish. However, in Spanish, "plátano" refers to the banana fruit (a plant of the genus Musa), not the plane tree. The etymological connection to the plane tree is historically accurate, but the semantic shift occurred as the word was applied to the banana plant, likely due to superficial similarities between the plants.