Abu Huraira (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings of Allah be upon him) said: None of you should call grapes "Karam," for "Karam" refers to a Muslim man.
It is narrated from Sayyiduna Wa'il bin Hujr (may Allah be pleased with him) that the Noble Prophet (peace and blessings of Allah be upon him) said: Do not call (grapes) "karm", rather call them "inab" or "hablah".