The grapefruit is a late addition to the citrus family, first appearing in Barbados in the 17th century. At first it was seen as a kind of pomelo, called shaddocks at the time, after the legendary Captain Shaddock, who supposedly brought the pale, pithy fruit to the Caribbean.
Around 1750, the grapefruit -- a hybrid of the pomelo and orange -- began to be seen as a species in its own right, and was given its own name: the “forbidden fruit,” named for that which Adam and Eve tasted despite God's prohibition.
The first reference we have to the fruit being called “grape fruit” is in John Lunan’s "Hortus Jamaicensis," printed in Jamaica in 1814, apparently in reference to some varieties of the fruit growing in clusters such as those of the grapevine.
Meanwhile, the first grapefruits were grown in Israel around 1900 – in Petah Tikva. But it only became popular after Abraham Bril, an agronomer working for the Baron Rothschild, brought a over a seedless variety called marsh, from Florida, in 1914.
The fruit only received a Hebrew name at the end of the 1920s, when Yisrael Weinberg called it eshkolit (esh-ko-LIT), which he derived from the word for a cluster of grapes -- eshkol -- in a kind of translation of the English word grapefruit.