Parthenocarpic, translated from the Latin basically means seedless or the fruit set without seed. Parthenocarpic cucumbers will produce produce seedless cucumbers if grown isolated from other varieties. Once they have been pollinated by another cucumber, the resulting fruit is generally undesirable both in taste and form.
They are best suited for greenhouse or indoor scenarios where no pollinators are present. They differ slightly from Gynoecious in that pollination of a Gynoecious - Female Cucumber will not necessarily produce an undesirable fruit. Parthenocarpic cucumbers are nearly all gynoecious, meaning that they only produce female flowers. However, not all gynoecious cucumbers are parthenocarpic.
A few examples of Parthenocarpic cucumbers are Little Leaf, Diva, Rocky, Socrates, Sweet Success, Tyria.