Octorad is the name for a style of stadium architecture in the late 1960s. The term suggests eight radiuses, the design incorporating four arcs of a large circle to comprise most of the structure, and four arcs of a smaller circle to round out the corners. It was a variant on the archetypal multi-purpose stadiums of the time, many of which were either conventionally circular or oval, and were often criticized for poor sight line angles for many spectators at baseball and football games.

The most prominent examples of the octorad style were San Diego Stadium in San Diego, which opened in 1967, and Veterans Stadium in Philadelphia, which opened in 1971. Both stadiums accomplished the goal of providing better sight lines for spectators. However, the architecture of those two stadiums still put a large majority of the fans far away from the action.

Other terms sometimes used for this design were "super circle" and "square circle".

The term "octorad" was coined by architect Hugh Stubbins in 1966 while drafting plans for what would become Veterans Stadium. He gave the following explanation for the design upon presenting his stadium proposal to the City of Philadelphia that September:

"It is made with eight points of radii located on two concentric circles so that the arcs of the four long radii locate the points of origin of the four smaller radii on the inner concentric."

Ronald Knabb Jr., who worked alongside Stubbins on the octorad as lead designer, broke down the word's etymology as follows: "'Octo' is Latin for numeral eight. 'Rad' is short for radius. There are eight points of radius on a circle. Connect them with straight lines of chords, and you have the shape of the stadium."

With the new Philadelphia stadium intended to host football for the Eagles and baseball with the Phillies, Stubbins was keen on a design that would maximize seating capacity while providing good viewpoints for spectators. He came up with the octorad, which was described as an "approximate circle" whose shape ensured "no one would get a sore neck from trying to see the game". The additional seats for football would be tarped off for baseball. The shape also would have allowed for easy construction of a roof if desired, and Stubbins expressed hope of installing a dome bigger than the Astrodome's though Veterans Stadium remained open-air. It competed against a traditional rectangular design from George M. Ewing Co. that was criticized by Phillies president R. R. M. Carpenter Jr. for not being baseball-adequate.

The octorad was praised by the Eagles and the city. Eagles owner Jerry Wolman called it "without question the finest we have ever seen", while Philadelphia managing director Fred T. Corletto argued that "because of its unique shape, it will put Philadelphia sports closer to the field of action than in any other multi-purpose stadium in the nation." Although construction was delayed due to deadlock over cost, with the octorad exceeding the public funding approved by voters, the city still stressed the desire to use the octorad. Eagles vice president Ed Snider called it a "composite of all problems and compromise"; while the Phillies were initially skeptical, Snider added "both teams loved it" in the end.