Citron
A source of confusion is that "citron" or similar words in French (and other languages), and English are false friends, as they refer to the lemon. Indeed, into the 16th century, the English name "citron" included the lemon and perhaps the lime as well.
Sweet lemon
Sweet lemon and sweet lime refer to many citrus hybrids that contain low acid pulp and juice. They are hybrids often similar to non-sweet lemons or limes, but with less citron parentage. Sweet limes and lemons are not sharply separated:
The same plant may also be known by different names:
The sweet lemons and sweet limes are not derived from either lemons or the more common limes, nor do they represent a monophiletic grouping, having arisen from distinct citrus hybridizations. Plants and fruits with the common name sweet lemon or sweet lime include: