semidiameter

[ sem-ee-dahy-am-i-ter, sem-ahy- ]

/ ˌsɛm i daɪˈæm ɪ tər, ˌsɛm aɪ- /

half of a diameter; radius.

Origin of semidiameter

First recorded in 1545–55; semi- + diameter

Each semicircular niche was about a foot in its semidiameter.

Passages From the French and Italian Notebooks, Volume 1 |Nathaniel Hawthorne
As the semidiameter was only 28 inches, this large tree could have been but 168 years old.

Missionary Travels and Researches in South Africa |David Livingstone
Whereby it dothe well appeare, that the side of anye sisangle made in a circle, is equalle to the semidiameter of the same circle.

The Path-Way to Knowledg |Robert Record
Then at the ende of eche semidiameter, I draw a touche line, whiche shall make righte angles with the semidiameter.

The Path-Way to Knowledg |Robert Record

For a right line either from the center unto the touch-point; or from the touch point unto the center is radius or semidiameter.

The Way To Geometry |Peter Ramus