Citron
The citron ("Citrus medica") is a large fragrant citrus fruit with a thick rind. It is one of the original citrus fruits from which all other citrus types developed through natural hybrid speciation or artificial hybridization. Though citron cultivars take on a wide variety of physical forms, they are all closely related genetically. It is used widely in Asian cuisine, and also in traditional medicines, perfume, and for religious rituals and offerings. Hybrids of citrons with other citrus are commercially prominent, notably lemons and many limes.
Kabbad
The Kabbad refers to a citron-like fruit or citrus hybrid which was first described in 1963 by the Moroccan professor Henri Chapot, in his article named ""Le Cédrat Kabbad et deux autres variétés de cédrat"", who remarked it to be a biological hybrid between the citron and the orange sourcing from Damaskus, Syria.
Following is from The Citrus Industry vol. 1 Chap.4: