Shaddock
2 of the 7 encyclopedias on this shelf carry an entry for Shaddock. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
sometimes called pompelmoose, a large species of orange, attaining the diameter of seven or eight inches, with a white, thick, spongy, and bitter rind, and a red or white pulp of a sweet taste, mingled with acidity. It is a native of China and Japan, and was brought to the West Indies by a Captain Shaddock, from whom it derived its name. In the United States and California. Grapefruit or pomelo is a variety of shaddock. SHADOW. (1) Shade within defined limits; the figure of a body projected on the ground, etc., by the interception of light; obscurity or deprivation of light, or plane, and repapparent on a surface resenting the form of the body which intercepts the rays of light. (2) Darkness, gloom, shade, obscurity. (3) The dark part of a picture; the representation of comparative deficiency or deprivation of light; shade. (4) A reflected image, as in a mirror or water, hence, any image or portrait. In optics, shadows are, theoretically considered, of two kinds, geometrical and physical. If a shadow be supposed to be produced by the interception of light proceeding from a single mathematical point, it will be well defined by straight lines proceeding from the point, and grazing the intervening object. But as every luminous body is possessed of some magnitude, and, therefore, emits light from many points, the shadow is not precisely defined, but consists of a portion in perfect shadow, or to which no luminous rays have access, and penumbra, to which some rays have access. In the former case the theoretical shadow is a geometric one, in the latter physical, i. e., such as actually occurs in nature.
Aiton's Encyclopedia (1910)
the handsomest tree of the orange group. It is a native of the Malayan and Polynesian Islands, and is cultivated in Florida, California, the West Indies , India, and other tropical and semitropical countries for its fruit, also called the shaddock. The tree attains an extreme height of forty feet. It has large ovate leaves and, like the orange, white flowers. There are several varieties. The fruit, which resembles the grapefruit, except that it is larger, weighing in some varieties as much as fifteen pounds, has a light yellow, in some cases a pink rind, which is very bitter. The pulp, which is arranged in sections like the orange, may be yellow, pink, green, or crimson. It is juicy, luscious, and refreshing, but is considered inferior to grapefruit. The fruit grows in clusters.