The Latin word *curvilineus* came to our **language** as **curved** . This adjective is used to qualify that formed by **curve lines** . A **curve** , on the other hand, is that which is moving continuously away from the straight direction, without creating an angle.

Is called **curvilinear angle** , in this framework, at **angle** formed by **curve lines** . This means that its sides are not straight, but curved. If the angle has a curved line and a straight line, it is qualified as mixtilinear.

A **curvilinear movement** , on the other hand, is a **circular, oscillatory or parabolic displacement** . A competition vehicle disputing a **race** in an oval-shaped circuit it performs a curvilinear movement.

If the **trajectory** through which a particle travels is known by the observer, it is considered appropriate to describe the movement using the coordinate axes *n* (which acts as normal to the trajectory) and *t* (It is tangent to the trajectory), and at the moment it is considered they have their origin located in the particle. If the trajectory is curved, then one can speak of an elliptical movement.

If we consider a particle that moves in a **flat** on a fixed curve, at any moment you will find yourself in the position *s*, which is measured taking into account the point *OR*. For a coordinate system whose origin is a fixed point of the curve and at the instant observed it coincides with the position of the particle, the following will occur:

***** the t-axis will be tangent to the curve and positive in the direction in which s is increased (the positive direction of the **displacement** of the particle);

***** said axis is perpendicular to n in its positive direction pointing towards the center of the curve;

***** the plane that contains them both is called *rocking* or *hugger*. In a case like this, it would be fixed in the plane of displacement.

Given that the **particle** It is in motion, position is a function of time. The direction of the velocity is always tangent to its trajectory, and to calculate its magnitude it is necessary to derive the time from the trajectory function.

If we have a curvilinear motion on an XY plane, with the corresponding axes and the **origin** determined, the magnitudes that describe it are a position vector at a given moment, and can be represented with the letters *r* and *t*respectively. Let's not forget that along the entire trajectory of the particle, it will pass through a set of points; at each instant, one of them can be identified in relation to the instant.

In short, everything that has curves, or is characterized by them, can be mentioned as curvilinear. For example: *“The curvilinear layout of circuit it makes cars can't reach great speed ”*,

*"The Finnish company surprised to present a curvilinear phone"*,

*"The curvy soda container is very easy to grab"*.

The idea of curvilinear is often used with respect to female forms. When a **woman** It presents marked curves in its figure, it is said to be curvilinear. This is an aesthetic feature that is usually considered attractive: *“The Italian actress dazzled on the beach with her curvy body”*, *"The curvy figure of the model captivated the gallant, who barely saw her approached to talk to him"*, *“I like curvilinear women”*.

The measures that are usually mentioned as the ideal of the **beauty** female (90 centimeters of bust, 60 centimeters of waist and 90 centimeters of hip) are linked to **curvy women** . These different measures assume the existence of sharp curves in the silhouette.