of tariffs, imports and customs. Justice Horace Gray delivered the opinion of the Court in holding that the Tariff Act of 1883 used the ordinary meaning of the words "fruit" and "vegetable", instead of the technical botanical meaning.

In 1883, President Chester A. Arthur signed the Tariff Act of March 3, 1883, requiring a tax to be paid on imported vegetables, but not fruit. The John Nix & Co. company filed a suit against Edward L. Hedden, Collector of the Port of New York, to recover back duties paid under protest. They argued against the tariff by pointing out that, botanically, a tomato is a fruit due to its seed-bearing structure growing from the flowering part of a plant.

At the trial, the plaintiffs' counsel entered into evidence definitions of the words "fruit" and "vegetables" from Webster's Dictionary, Worcester's Dictionary, and the Imperial Dictionary. They called two witnesses, who had been in the business of selling fruit and vegetables for 30 years, and asked them, after hearing these definitions, to say whether these words had "any special meaning in trade or commerce, different from those read".

Both the plaintiffs' counsel and the defendant's counsel made use of the dictionaries. The plaintiffs' counsel read in evidence from the same dictionaries the definitions of the word tomato, while the defendant's counsel then read in evidence from Webster's Dictionary the definitions of the words pea, eggplant, cucumber, squash, and pepper. Countering this, the plaintiff then read in evidence from Webster's and Worcester's dictionaries the definitions of potato, turnip, parsnip, cauliflower, cabbage, carrot and bean.

Justice Gray, citing several Supreme Court cases (Brown v. Piper, 91 U.S. 37, 42, and Jones v. U.S., 137 U.S. 202, 216) stated that when words have acquired no special meaning in trade or commerce, the ordinary meaning must be used by the court. In this case dictionaries cannot be admitted as evidence, but only as aids to the memory and understanding of the court. Gray acknowledged that botanically, tomatoes are classified as a "fruit of the vine"; nevertheless, they are seen as vegetables because they were usually eaten as a main course instead of being eaten as a dessert. In making his decision, Justice Gray mentioned another case where it had been claimed that beans were seeds — Justice Bradley, in Robertson v. Salomon, 130 U.S. 412, 414, similarly found that though a bean is botanically a seed, in common parlance a bean is seen as a vegetable. While on the subject, Gray clarified the status of the cucumber, squash, pea, and bean.

Nix has been cited in three Supreme Court decisions as a precedent for court interpretation of common meanings, especially dictionary definitions. (Sonn v. Maggone, 159 U.S. 417 (1895); Saltonstall v. Wiebusch & Hilger, 156 U.S. 601 (1895); and Cadwalader v. Zeh, 151 U.S. 171 (1894)). Additionally, in JSG Trading Corp. v. Tray-Wrap, Inc., 917 F.2d 75 (2d Cir. 1990), a case unrelated to Nix aside from the shared focus on tomatoes, a judge wrote the following paragraph citing the case:

In common parlance tomatoes are vegetables, as the Supreme Court observed long ago [see Nix v. Hedden 149 U.S. 304, 307, 13 S.Ct. 881, 882, 37 L.Ed. 745 (1893)], although botanically speaking they are actually a fruit. [26 Encyclopedia Americana 832 (Int'l. ed. 1981)]. Regardless of classification, people have been enjoying tomatoes for centuries; even Mr. Pickwick, as Dickens relates, ate his chops in "tomata" sauce.

In 2005, supporters in the New Jersey legislature cited Nix as a basis for a bill designating the tomato as the official state vegetable.