First Known Use: 14th century
Dictionary
diameter
noun di·am·e·ter \dī-ˈa-mə-tər\
: a straight line from one side of something (such as a circle) to the other side that passes through the center point
: the distance through the center of something from one side to the other
Full Definition of DIAMETER
1
: a chord passing through the center of a figure or body
2
: the length of a straight line through the center of an object
3
: a unit of enlargement used with a number to indicate magnification by a lens or optical system <an object one millimeter wide magnified 40 diameters appears 40 millimeters wide>
— di·am·e·tral \-ˈa-mə-trəl\ adjective
See diameter defined for English-language learners
See diameter defined for kids
ADVERTISEMENT
Origin of DIAMETER
Middle English diametre, from Middle French, from Latin diametros, from Greek, from dia- + metron measure — more at measure
Other Mathematics and Statistics Terms
Rhymes with DIAMETER
DIAMETER Defined for Kids
diameter
noun di·am·e·ter \dī-ˈa-mə-tər\
Definition of DIAMETER for Kids
1
: a straight line that runs from one side of a figure and passes through the center <Measure the diameter of the circle.>
2
: the distance through the center of an object from one side to the other : thickness <the diameter of a tree trunk>
Word Root of DIAMETER
The Greek word metron, meaning “measure,” gives us the root metr. Words from the Greek metron have something to do with measuring. A thermometer is an instrument that measures temperature. A diameter is the measurement across the center of a circle. The metric system is a system used for measuring size, weight, and volume. A perimeter is the measurement of the outside of a figure or shape.
Medical Dictionary
diameter
noun di·am·e·ter \dī-ˈam-ət-ər\
Medical Definition of DIAMETER
1
: a unit of magnification for an optical instrument equal to the number of times the linear dimensions of an object are apparently increased <a microscope magnifying 60 diameters>
2
: one of the maximal breadths of a part of the body <the transverse diameter of the inlet of the pelvis>
Learn More About DIAMETER
Browse
Next Word in the Dictionary: diameter tapePrevious Word in the Dictionary: diambAll Words Near: diameter
ADVERTISEMENT
Seen & Heard
What made you want to look up diameter? Please tell us where you read or heard it (including the quote, if possible).