curl

curl

In mathematics, a differential operator that can be applied to a vector-valued function (or vector field) in order to measure its degree of local spinning. It consists of a combination of the function's first partial derivatives. One of the more common forms for expressing it is: in which v is the vector field (v₁, v₂, v₃), and v₁, v₂, v₃ are functions of the variables x, y, and z, and i, j, and k are unit vectors in the positive x, y, and z directions, respectively. In fluid mechanics, the curl of the fluid velocity field (i.e., vector velocity field of the fluid itself) is called the vorticity or the rotation because it measures the field's degree of rotation around a given point.

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(1) A programming environment for developing rich Internet applications (RIAs) from Curl, Inc., Cambridge, MA (www.curl.com). Conceived at MIT, Curl combines HTML markup with an object-oriented programming language. The user's machine requires the Curl runtime engine and browser plug-in for execution. The first Curl implementation was released in 2002. See RIA.

(2) (cURL) A command line utility for executing functions with URL-oriented protocols such as FTP and HTTP. Pronounced "C-URL," there are versions for Unix, Linux, Windows, Mac and other operating systems. For more information, visit http://curl.haxx.se.