late 14c., from Old French diametre, from Latin diametrus, from Greek diametros (gramme) "diagonal of a circle," from dia- "across, through" (see dia-) + metron "a measure" (see meter (n.2)).
例文
1. This hole was a scant.23 inches in diameter .
この穴の直径は0.23インチしかありません。
2.the diameter of a tree trunk
幹の直径
3.A diameter passes through the Center of a circle.
直径は円心から通り抜けている.
4.The diameter and the circumference of a circle correlate.