Note: The Old English n-stem croppa is matched by Old High German kropfo "crop of a bird, bulbous onion." Old Icelandic krov "slaughtered animal with the entrails removed" points to an original paradigm *kruƀan- : *kruƀn-, with the latter resulting in *kruppa- by loss of the nasal, devoicing, and gemination (Kluge's Law). The early meaning of the etymon and its later semantic bifurcations are difficult to reconstruct with certainty. An original sense "something rounded, bulge, swelling" may have led, on the one hand, to "cavity in a slaughtered animal after the entrails are removed" and hence "body, corpse" (meanings in North Germanic and Middle Dutch), and on the other to "swelling in the throat, crop of a bird, goiter." The sense "sprout, bud" in West Germanic is a further specification of "swelling." The later development in English is not paralleled in the other languages. The sense "sprout, sprig" seems to have been generalized to "structures terminating a plant, as fruit, seeds, umbels" and then, on the one hand, to "upper part, tip or end of an object" (such as the stock of a whip) and, on the other hand, to "harvested fruit of a plant, yield of such harvested products in a season." Compare croup entry 1, group entry 1. See R. Lühr, Expressivität und Lautgesetz im Germanischen, Heidelberg, 1988, p. 235; R. Lühr et al., Etymologisches Wörterbuch des Althochdeutschen, Band 5 [2014], columns 816-18; G. Kroonen, Etymological Dictionary of Proto-Germanic, Brill, 2013, p. 307.

Note: The phrasal verb crop up is dependent on a geological sense of crop, "(of rock strata) to appear at the surface," a coal miners' term in the West Midlands in the seventeenth century, which is apparently a development of the noun sense "tip, end" ("to show itself at the exposed end"). Compare outcrop entry 1.