semidiameter
Center to edge
Semidiameter is half the diameter of a circle or sphere—equivalent to the radius.
The term appears in astronomy and navigation, where it describes the angular distance from the center of a celestial body to its edge: The sun's semidiameter is about 16 arc minutes.
Though radius serves the same geometric purpose, semidiameter persists in technical contexts where tradition favors it.
Center-to-perimeter distance
- circumferenceCircle's outer measurement
- circleCurved closed shape
- arcCurved line segment
- chordNotes sounded simultaneously
sector · tangent · ellipse · radial · plane geometry · inscribed · circumscribed · curvature
Position change from different vantages
- transitMovement between places
- eclipseCelestial body blocks another
- elongationIncrease in length
- astronomical unitEarth-to-Sun distance standard
Tool measuring thickness or diameter
- micrometerMillionth of a meter
- gaugeStandard of measurement
- precisionAccuracy of measurement
- metrologyScience of precise quantification
surveying · calibration · dimension · proportion · scale · metric · standard · theodolite
radius
Center-to-perimeter distance
- circumferenceCircle's outer measurement
- circleCurved closed shape
- arcCurved line segment
chord · sector · tangent · ellipse · radial · plane geometry · inscribed · circumscribed · curvature · polar coordinates
parallax
Position change from different vantages
- transitMovement between places
- eclipseCelestial body blocks another
- elongationIncrease in length
caliper
Tool measuring thickness or diameter
- micrometerMillionth of a meter
- gaugeStandard of measurement
- precisionAccuracy of measurement
metrology · surveying · calibration · dimension · proportion · scale · metric · standard · theodolite · sextant
diameter, semi, semicircle, semicolon, semicircular, semiconscious, diameters, diametric, diametrically