base [bases](cooking, painting, pharmacy: basic but essential component or ingredient) noun [UK: beɪs] [US: ˈbeɪs]
ingredient [ingredients](substance present in a mixture) noun [UK: ɪn.ˈɡriː.dɪənt] [US: ɪŋ.ˈɡriː.diənt]What's the secret ingredient? = Qual è l'ingrediente segreto?