Cases of word usage

1) a public meeting at which goods are sold to the person offering the most money (auction)

2) the system of weights used, before metrication, in most English-speaking countries (1 pound = 16 ounces), used for all goods except precious metals and stones, and medicines (avoirdupois)

3) forming, of, the main, most important or useful part (basic)

4) the most basic or simplest parts (basics)

5) most superior in quality (of a group) (best)

6) most important (cardinal)

7) general; including many or most things (catholic)

8) most important (chief)

9) the most interesting, intense, violent, energetic etc part (of an event, game, speech, storm etc) (climax)

10) the part (of a problem) that is the most difficult to solve (crux)