Correct spelling for the English word "grisson" is [ɡɹˈɪsən], [ɡɹˈɪsən], [ɡ_ɹ_ˈɪ_s_ə_n] (IPA phonetic alphabet).
The word "grisson" is derived from the French word "gris", which means "gray". Grissaille, the root of "grisson", is a painting technique that utilizes shades of gray to create a monochromatic effect. The word later came to signify a gray-haired person or an old man, hence the modern meaning of "grisson" as an elderly or aging individual.