The leaves of pin oak are glossy green and measure approximately 5 inches (12.7 cm) in length. Each leaf has five bristle-tipped lobes with deep U-shaped sinuses reaching close to the midrib. The elliptic leaves display their widest area in the middle, maintaining the same green color on both sides without a glaucous texture. Veins are noticeable, and tan tufts of hairs can be found at the axils. In fall, leaves turn dark red to russet, often persisting into winter on younger trees.

The flowers of pin oak are distinct and varied. Male flowers form in pendulous, drooping clusters, appearing yellow or yellowish-green, measuring around 2 to 4 inches (5 to 10 cm) long. Female flowers, found on short spikes, are less conspicuous and grow individually or in small clusters from the axils of the current year’s leaves. The pistillate flowers have short stalks and they typically bloom from March to April, contributing to the plant's reproductive cycle.

The stem of pin oak is smooth, slender, and has a distinctive reddish-brown color. Typically, it measures between 1/4 to 3/8 inch (6-10 mm) in diameter. The stems display a characteristic branching pattern, often developing small, pointy side branches. Unique to its texture, the surface remains mostly devoid of significant ridges or furrows. This combination of smoothness, slenderness, and reddish-brown hue makes the stem of pin oak easily distinguishable.

The fruit of pin oak are diminutive acorns, typically measuring 1/4 to 1/2 inch in diameter. These globular nuts present singly or in small clusters of 2 to 3. As they mature, their hue transitions from green to a light tan or reddish-brown. Encasing the acorns are shallow, thin cups that envelop about 1/4 to 1/3 of the nut, characterized by a smooth, relatively unadorned surface. They are short-stalked, and these acorns make their appearance during the autumn months of October and November. Only after 15 to 20 years does pin oak begin to yield these fruits.