| 单词 | radius |
|---|---|
| 音标 | ['reidjəs] |
| 解释 | n.半径 |
| 红宝书 | 【英】 n. 半径 (a straight line going from the side of a circle to the center) 【考】 spoke : hub / radius : center(轮辐到轮轴距离相同 /半径到圆心距离相同) |
| 字源 | radius (n.) 1590s, "cross-shaft," from Latin radius "staff, stake, rod; spoke of a wheel; ray of light, beam of light; radius of a circle," of unknown origin. Perhaps related to radix "root," but Tucker suggests connection to Sanskrit vardhate "rises, makes grow," via root *neredh- "rise, out, extend forth;" or else Greek ardis "sharp point." The geometric sense first recorded 1610s. Plural is radii. Meaning "circular area of defined distance around some place" is attested from 1953. Meaning "shorter bone of the forearm" is from 1610s in English (the Latin word had been used thus by the Romans). |
| 不择手段背单词 | n. 半径 【记】源于: radiate(v 放射)从圆心放射出去的线－radius 【类】spoke: hub = radius: center辐条到轮轴距离相同 = 半径到圆心距离相同 |
| 趣味全助记 | 【记】radi- 辐射, 雷达的辐射是从中心顺逆时针地沿半径扫 |
Learn with these flashcards. Click next, previous, or up to navigate to more flashcards for this subject.
Next card: Raffish dissemble preen 放荡的 ræfiʃ a.粗俗的；俗艳的 考 ingenuous
Previous card: Racy adj sense reisi a.活泼的，生动的 英 活泼的，生动的 amusing
Up to card list: 极品GRE红宝书(简体中文)