- Cactus League (1948)
- Can of Corn (1926)
- Can’t Buy a Hit (1915)
- Career Minor Leaguer (1956)
- Catcher’s Box (1883)
- Caught Leaning (1909)
- Caught Stealing (1874)
- Cellar Dweller (1906)
- Center Fielder (1862)
- Change of Pace (1867)
- Changeup (1934)
- Charge the Mound (1949)
- Charley Horse (1886)
- Checked Swing (1912)
- Cheese (1975)
- Chin Music (1865)
- Choke Up (1907)
- Circus Catch (1878)
- Clean the Bases (1878)
- Cleanup – Cleanup Hitter – Cleanup Man – Cleanup Position (1906)
- Clear the Bases (1868)
- Clear the Fence (1884)
- Clown Prince (1923)
- Clubhouse Lawyer (1914)
- Clutch (1922)
- Coacher (1874)
- Coax a Pass (1906)
- Color Line (1877)
- Come Through in the Clutch (1925)
- Come Up Throwing (1912)
- Command (1862)
- Competitive Balance (1918)
- Complete Game (Pitcher) (1889)
- Conference (1910)
- Consecutive Game Hitting Streak (1918)
- Contact Hitter (1964)
- Control Pitcher (1914)
- Corner (1890)
- Count the Stitches (1894)
- Crack of the Bat (1891)
- Crooked Number (1978)
- Crowd the Plate (1896)
- Curtain Raiser (1898)
- Curveball (1876)
- Curveballer (1910)
- Cut Fastball (1970)
- Cycle (1920)
- Cyclone Pitcher (1884)
