Definitions of lemon:

• noun:   an artifact (especially an automobile) that is defective or unsatisfactory
• noun:   a distinctive tart flavor characteristic of lemons
• noun:   yellow oval fruit with juicy acidic flesh
• noun:   a small evergreen tree that originated in Asia but is widely cultivated for its fruit
• noun:   a strong yellow color
• name:  A surname (common: 1 in 16666 families; popularity rank in the U.S.: #2018)