Main Difference
The main difference between Curveball and Slider is that the Curveball is a type of pitch in baseball and Slider is a baseball pitch.
Curveball
The curveball is a type of pitch in baseball thrown with a characteristic grip and hand movement that imparts forward spin to the ball, causing it to dive in a downward path as it approaches the plate. Varieties of curveballs include the 12-6 curveball and the knuckle curve. Its close relatives are the slider and the slurve. The “curve” of the ball varies from pitcher to pitcher.
Outside the context of baseball, variants of the expression “to throw a curveball” essentially translate to introducing a significant deviation to a preceding concept.
Slider
In baseball, a slider is a breaking ball pitch that tails laterally and down through the batter’s hitting zone; it is thrown with less speed than a fastball but greater than the pitcher’s curveball.
The break on the pitch is shorter than that of the curveball, and the release technique is ‘between’ those of a curveball and a fastball. The slider is similar to the cutter, a fastball pitch, but is more of a breaking ball than the cutter. The slider is also known as a yakker or a snapper.
Curveball (noun)
A forespin pitch thrown by rotating the index and middle fingers down and resulting in motion down “curve”
“He bit on a curveball in the dirt.”
Curveball (noun)
An unexpected turn of events initiated by an opponent or chance.
“Life has thrown him a few curveballs.”
Curveball (verb)
To throw a curveball.
Slider (noun)
Agent noun of slide: one who slides.
Slider (noun)
A sliding door.
Slider (noun)
A pitch thrown with added pressure by middle and ring fingers yielding a combination of backspin and sidespin, resulting in a motion to the left when thrown by a right handed pitcher.
“The closer had a wicked slider that was almost unhittable.”
Slider (noun)
A similar delivery in which the wrist and ring finger work to impart backspin to the ball.
Slider (noun)
A small hamburger.
“We ordered five sliders.”
Slider (noun)
A piece of Teflon or similar material attached to a curling shoe that allows the player to slide along the ice.
Slider (noun)
A widget allowing the user to select a value or position on a sliding scale.
Slider (noun)
A slideshow on a web page.
Slider (noun)
Pseudemys rugosa, the red-bellied terrapin.
Slider (noun)
A rectangle of fabric that helps produce an orderly parachute deployment.
Slider (noun)
synonym of slide