An eephus pitch (also spelled ephus) in baseball is a very high-arcing off-speed pitch. The delivery from the pitcher has very low velocity and often catches the hitter off-guard. The eephus pitch is thrown overhand like most pitches, but is characterized by an unusual, high-arcing trajectory. The corresponding slow velocity bears more resemblance to a slow-pitch softball delivery than to a traditional baseball pitch. It is considered a trick pitch because, in comparison to normal baseball pitches, which run from 70 to 100 miles per hour (110 to 160 km/h), an eephus pitch appears to move in slow motion at 55 mph (89 km/h) or less, sometimes as low as 35 mph (56 km/h).
Its invention is attributed to Rip Sewell of the Pittsburgh Pirates in the 1940s, although according to historians John Thorn and John Holway, the first pitcher to throw a big blooper pitch was Bill Phillips, who played in the National League on and off from 1890 through 1903. The practice then lay dormant for nearly 40 years until Sewell resurrected it. According to manager Frankie Frisch, the pitch was named by outfielder Maurice Van Robays. When asked what it meant, Van Robays replied, "'Eephus ain't nothing, and that's a nothing pitch." Although the origin is not known for certain, "eephus" may come from the Hebrew word אפס (pronounced EF-ess), meaning "zero".