夕陽 [せきよう] – setting sun
夕 [セキ・ゆう] – evening
陽 [ヨウ・ひ] – the sun

Note that, in addition to meaning “sun,” 陽 also refers to half of the famous “opposites” of Daoism: 陰陽 yin/yang in Chinese, in/you in Japanese. Despite how it looks in romaji, it isn’t pronounced like the English word “you,” but rather like “yo!” with a longer “o” sound. Good reason to learn Hiragana, methinks.