Thomcord is a seedless table grape variety and a hybrid of the popular Thompson Seedless or sultanina grape (a Vitis vinifera variety) and Concord grape (a Vitis labrusca variety) Thomcord was developed in 1983 by Californian grape breeders working for the Agricultural Research Service (ARS), an agency of the United States Department of Agriculture , as part of a test to better understand a new seedless grape breeding procedure.

Its aromatic, "labrusca" flavor is similar to that of Concord, but mellowed by the mild, sweet taste from Thompson Seedless. Thomcord grows well in hot, dry climates, ripens between late July and mid-August, and tolerates powdery mildew. It is a productive variety, yielding an average of 15.1 kg (33 lb) of grapes per vine, but has produced as much as 32 kg (71 lb) per vine in grower trials. The berries weigh between 2.72 and 3.38 g (0.096 and 0.119 oz) and have a medium-thick, blue-black skin that adheres to the fruit, unlike Concord, which has a thick skin that can slip off the pulp easily. The aborted seeds in the fruit body are relatively small, but larger than those in Thompson Seedless.

The plant is not restricted for propagation and distribution. Virus-free propagation material is available in the United States from the Foundation Plant Services (FPS) at the University of California, Davis, and its genetic material is archived at the National Plant Germplasm System. After 17 years of testing, it was declared ready for use in 2003. It is currently available in supermarkets.

Thomcord grape is a hybrid of Thompson Seedless grape (Vitis vinifera, or Sultanina), which is popular in American (?) supermarkets during the summer, and seeded Concord grape (Vitis labrusca), commonly used to make grape juice and jelly. It is a plump, juicy, seedless table grape and is slightly firmer than Concord. Thomcord has a blue-black skin with medium thickness and a whitish bloom. Unlike Concord, whose tough skin separates easily from the fruit, Thomcord has a more edible skin that clings to the flesh, much like Thompson Seedless. It has an aromatic flavor, similar to the Concord in taste ("labrusca"), though lighter due to the sweet, mild taste from Thompson Seedless.

Thomcord is suitable for hot, dry growing conditions, more so than Concord and other Concord seedless types. Its adaptability to hot dry climates was derived from Thompson Seedless. It grows well in California's vineyards, particularly the San Joaquin Valley, just like Thompson Seedless. The plant is tolerant of (but not resistant to) powdery mildew, and is less susceptible to the fungus than Ruby Seedless, but more susceptible than Mars, Venus, Niabell, and Cayuga White varieties. The fungus can affect its leaves, stems, rachis (stem of the grape cluster), and berries. The grape ripens in the summer (mid-season), between late July and mid-August.

Thomcord is a productive variety, with a yield comparable to Thompson Seedless. When two cordons (arms) of the vines are trained horizontally on wires ("bilateral-trained") and are pruned to remove most of the previous year's growth ("spur-pruned") during the winter, it can produce up to 13–16 kg (29–35 lb) per vine, or an average of 15.1 kg (33 lb). In 2002, cane-pruned vines of Thomcord were significantly more productive than Sovereign Coronation and were comparable to the Venus variety, averaging 21.3 kg (47 lb) per vine. Unlike Thompson Seedless, which has its cluster size thinned as a normal production practice, Thomcord's is not thinned because of its smaller cluster size. The grape clusters range in weight between 259 and 534 g (0.571 and 1.177 lb) and average 340 g (0.75 lb), have medium to slightly loose tightness (or are "well-filled", meaning the individual pedicels are not easily visible), and have a conical shape with a small wing.

Compared with Thompson Seedless, the berry weight and diameter of Thomcord are larger, but cluster tightness is similar. The berry length ranged between 18.2 and 18.3 mm (0.72 and 0.72 in) and the diameter ranged from 16.7 to 17.2 mm (0.66 to 0.68 in) in tests between 2001 and 2002. The berries weigh between 2.72 and 3.38 g (0.096 and 0.119 oz), averaging 2.85 g (0.101 oz) in 2002, which is on par with Venus, but heavier than Sovereign Coronation, and even more so than Thompson Seedless. The fruit's size has not been shown to increase appreciably by girdling the vines or by applying gibberellic acid when the berries set.

The aborted seeds of Thomcord are small, but in some years they can become sclerified (a thickening and lignification of the walls of plant cells and the subsequent dying off of the protoplasts), making them more noticeable inside the medium-soft flesh. There are usually two aborted seeds per berry, which averaged between 14 and 22.3 mg in 2001 and 2002. This varied in comparison to Venus depending on the year and location, was comparable to the Sovereign Coronation, and was significantly smaller than the Sovereign Rose and Saturn varieties. However, as with the other cultivars, it was consistently larger than Thompson Seedless, which had the smallest aborted seeds.