泽 (zé) is a bound morpheme (b.f.) that cannot stand alone as a free word; it always appears as a component of compound words. It has two main clusters of meaning: (1) 'marsh, swamp, body of water' as in 沼泽 (zhǎozé, swamp) and 湖泽 (húzé, lakes and marshes); (2) 'luster, sheen, gloss' as in 光泽 (guāngzé, luster) and 色泽 (sèzé, color and luster). The two senses are historically connected through the idea of water and shine, but they are distinct in modern usage. To use it naturally, memorize common compounds such as these.