A curve is an arched or bent shape, like the curve of a smiling mouth or the curve of a road that twists and turns as you drive along the coast.

As a noun, a curve can be any shape that deviates from being perfectly straight. You can trace a curve on a graph, throw an arcing pitch in baseball called a curve ball, or just admire the curves of the rolling hills in the distance. And as a verb, curve means to make or form this non-straight shape: "When she's happy, my dog's tail curves up over her back."

Definitions of curve
  1. noun
    the trace of a point whose direction of motion changes
    synonyms: curved shape
    see moresee less
    straight line
    a line traced by a point traveling in a constant direction; a line of zero curvature
    show 37 types...
    hide 37 types...
    Gaussian curve, Gaussian shape, bell-shaped curve, normal curve
    a symmetrical curve representing the normal distribution
    a bend or curve, as in a stream or river
    closed curve
    a curve (such as a circle) having no endpoints
    a double curve resembling the letter S
    the curve theoretically assumed by a perfectly flexible and inextensible cord of uniform density and cross section hanging freely from two fixed points
    Cupid's bow
    the double curve of the upper lip when considered to resemble Cupid's bow
    undulation, wave
    an undulating curve
    the exterior curve of an arch
    something in a thin curved form (like the neck of a goose)
    the interior curve of an arch
    bend, crook, turn, twist
    a circular segment of a curve
    crotchet, hook
    a sharp curve or crook; a shape resembling a hook
    a curve that is tangent to each of a family of curves
    a continuous portion of a circle
    crenation, crenature, crenel, crenelle, scallop
    one of a series of rounded projections (or the notches between them) formed by curves along an edge (as the edge of a leaf or piece of cloth or the margin of a shell or a shriveled red blood cell observed in a hypertonic solution etc.)
    a plane curve traced by a point circling about the center but at increasing distances from the center
    helix, spiral
    a curve that lies on the surface of a cylinder or cone and cuts the element at a constant angle
    a curve that reverses the direction of something
    sinuosity, sinuousness
    having curves
    a curved shape in the vertical plane that spans an opening
    bell, bell shape, campana
    the shape of a bell
    arc, bow
    something curved in shape
    a curved shape tapers at the ends, like the moon in its first and last quarters
    quadric, quadric surface
    a curve or surface whose equation (in Cartesian coordinates) is of the second degree
    line roulette, roulette
    a line generated by a point on one figure rolling around a second figure
    the graduated arc that is attached to an instrument for measuring angles
    a U-shaped curve in a stream
    an arc of colored light in the sky caused by refraction of the sun's rays by rain
    Jordan curve, simple closed curve
    a closed curve that does not intersect itself
    (biology) any hook-shaped process or part
    a bend or curve (especially in a coastline)
    double helix
    a pair of parallel helices intertwined about a common axis
    a quadric surface generated by rotating a hyperbola around its main axis
    a line generated by a point on a circle rolling along a straight line
    sine curve, sinusoid
    the curve of y=sin x
    a line generated by a point on a circle rolling around another circle
    a line generated by a point on a circle that rolls around inside another circle
    type of:
    a length (straight or curved) without breadth or thickness; the trace of a moving point
  2. noun
    the property possessed by the curving of a line or surface
    synonyms: curvature
    see moresee less
    curliness, waviness
    (of hair) a tendency to curl
    (of hair) lack of a tendency to curl
    type of:
    configuration, conformation, contour, form, shape
    any spatial attributes (especially as defined by outline)
  3. noun
    curved segment (of a road or river or railroad track etc.)
    synonyms: bend
    see moresee less
    blind bend, blind curve
    a curve or bend in the road that you cannot see around as you are driving
    a sharp bend in a road or river
    hairpin bend
    a U-shaped bend in a road
    type of:
    section, segment
    one of several parts or pieces that fit with others to constitute a whole object
  4. noun
    a line on a graph representing data
    see moresee less
    regression curve, regression line
    a smooth curve fitted to the set of paired data in regression analysis; for linear regression the curve is a straight line
    type of:
    a length (straight or curved) without breadth or thickness; the trace of a moving point
  5. noun
    a pitch of a baseball that is thrown with spin so that its path curves as it approaches the batter
    synonyms: bender, breaking ball, curve ball
    see moresee less
    type of:
    delivery, pitch
    (baseball) the act of throwing a baseball by a pitcher to a batter
  6. verb
    form a curl, curve, or kink
    synonyms: curl, kink
    see moresee less
    type of:
    change surface
    undergo or cause to undergo a change in the surface
  7. verb
    form an arch or curve
    synonyms: arc, arch
    see moresee less
    curve upward in the middle
    type of:
    bend, flex
    form a curve
  8. verb
    bend or cause to bend
    “the road curved sharply”
    synonyms: crook
    see moresee less
    curve or bend (something) back or down
    type of:
    bend, flex
    form a curve
  9. verb
    extend in curves and turns
    synonyms: twist, wind
    see moresee less
    wind or turn in volutions, especially in an inward spiral, as of snail
    form a spiral
    form a snake-like pattern
    type of:
    have the quality of being; (copula, used with an adjective or a predicate noun)
  10. verb
    turn sharply; change direction abruptly
    synonyms: cut, sheer, slew, slue, swerve, trend, veer
    see moresee less
    peel off
    leave a formation
    swerve off course momentarily
    type of:
    change orientation or direction, also in the abstract sense
Word Family

Test prep from the experts

Boost your test score with programs developed by’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week


  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week