【根】cuss＝to strike（打击），to shake（摇动）

discuss
To speak with another or others about; talk over.
To examine or consider (a subject) in speech or writing
vt. 讨论；论述，辩论

例句：
They discussed how to promote cooperation between the two countries.
他们讨论如何促进两国间的合作。
Mr. Wood refused to discuss the matter.
伍德先生拒绝讨论这件事。

percussive
of or relating to percussion especially : operative or operated by striking
having powerful impact
adj. 冲击的；叩诊的，敲击的

repercussion
An often indirect effect, influence, or result that is produced by an event or action.
A recoil, rebounding, or reciprocal motion after impact.
A reflection, especially of sound.
n. 反响；弹回；反射

concussion
A violent jarring; a shock. See Synonyms at collision.
An injury to an organ, especially the brain, produced by a violent blow and followed by a temporary or prolonged loss of function.
n. 冲击；震荡；脑震荡

concuss
to injure by concussion
vt. 震动；恐吓

例句：
He was caught by an avalanche and was seriously concussed.
他碰到雪崩，受到严重的脑震荡。

abacus
A manual computing device consisting of a frame holding parallel rods strung with movable counters.
n. 算盘

词源小故事

The adjective dusty, with its connotations of disuse and age, might seem to be an appropriate word to describe the abacus,since this counting device was used for solving arithmetical problems in the days before the advent of calculators and computers.Originally the abacus was, in fact, dusty.The source of our wordabacus, the Greek word abax, probably comes from Hebrew ’³b³q, “dust,” although the details of transmission are obscure.In postbiblical usage’³b³q meant “sand used as a writing surface.” The Greek wordabax has as one of its senses “a board sprinkled with sand or dust for drawing geometric diagrams.” This board is a relative of the abacus with movable counters strung on rods that is familiar to us.The first use of the wordabacus, recorded in Middle English in a work written before 1387, refers to a sand-board abacus, in this case, one used by the Arabs.The difference in form between the Middle English wordabacus and its Greek source abax is explained by the fact that Middle English actually borrowed Latin abacus, which came from the Greek genitive form (abakos ) of abax.

形容词dusty 一词带有废旧的隐含意义， 用这个词来描述算盘似乎是合适的，因为在计算器和计算机发明以前，算盘是用来解决算术问题的计算工具。事实上算盘原本就很容易脏。abacus 一词的希腊词源abax可能源自希伯来语abaq,意为“灰尘”，但具体的演变过程已不是很清楚了。abaq 在《圣经》之后的用法中有“用以书写的沙面”的意思。 希腊词abax 有“在一木板上洒上沙子或尘土用以画几何图形”之意。 这种木板就类似于我们所熟悉的装有可移动算子的算盘。abacus 第一次被使用是在一本1387年以前用中古英语写成的作品中， 指阿拉伯人使用的沙板算盘。中古英语的abacus 与其希腊词源 abax 词形上的区别是因为中古英语借用了拉丁文 abacus,而该拉丁文又是从希腊词abax 的所有格形式 abakos 演变而来的