The Italian translation of "Light" (the name of light blocks) is incorrect. Translators were likely given 0 context and thus translated it as an adjective ("chiaro", meaning "bright"), instead of translating it as a noun ("luce").
Expected translation: Luce
In-game translation: Chiaro
Fixed in 26.20.22. It’s now correctly translated as “Luce” (“light” as a noun).