diameter
n.
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).
〔李〕[dia-=through 穿；meter=measure 测量⇒“a measure through the centre 穿过中心的测量长度”→] n. line passing from one side to the other through the centre of a circle 直径