perimeter [puhrimiter] Word Origin noun
 the border or outer boundary of a twodimensional figure.
 the length of such a boundary.
 a line bounding or marking off an area.
 the outermost limits.
 Military. a fortified boundary that protects a troop position.
 Ophthalmology. an instrument for determining the peripheral field of vision.
Origin of perimeter 1585–95; French périmètre Latin perimetros (feminine) Greek perímetron (neuter). See peri, meter Related formspe·rim·e·ter·less, adjectivepe·rim·e·tral, per·i·met·ric [peruhmetrik] /ˌpɛr əˈmɛ trɪk/, per·i·met·ri·cal, adjectiveper·i·met·ri·cal·ly, adverbpe·rim·e·try, nounCan be confusedparameter perimeter British Dictionary definitions for perimetral perimeter noun
 maths
 the curve or line enclosing a plane area
 the length of this curve or line

 any boundary around something, such as a field
 (as modifier)a perimeter fence; a perimeter patrol
 a medical instrument for measuring the limits of the field of vision
Derived Formsperimetric (ˌpɛrɪˈmɛtrɪk) or perimetrical, adjectiveperimetrically, adverbperimetry, nounWord Origin for perimeter C16: from French périmètre, from Latin perimetros; see peri, meter Word Origin and History for perimetral perimeter n.
early 15c., “line around a figure or surface,” from Latin perimetros, from Greek perimetron “circumference,” from peri “around” (see peri) + metron “measure” (see meter (n.2)). Military sense of “boundary of a defended position” is attested from 1943.
perimetral in Medicine perimeter [pərĭm′ĭtər] n.
 The outer limits of an area; circumference.
 An instrument used to measure field of vision.
perimetral in Science perimeter [pərĭm′ĭtər]
 The sum of the lengths of the segments that form the sides of a polygon.
 The total length of any closed curve, such as the circumference of a circle.