Riyad as-Salihin (The Meadows of the Righteous)
by Imam Nawawi
330. Chapter: On it being disliked to call the grape the vine (karm)
1740. Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "Do not call the grape the vine (karm). The karm is the Muslim." [Agreed upon]
In one variant, "The karm is the heart of the believer."
1741. Wa'il ibn Hujr reported that the Prophet, may Allah bless him and grant him peace, said, "Do not say 'vine', but say 'grape and habala (another word for vine).'" [Muslim]