certain

• adj.確実な; 必然的な; 確かな; 間違いない; 確実性
• pron. ある; ある
• n. （ある）人の名前；（ポルトガル語）Sertaín；（フランス語）Sert?o

PIE *krei, *sker から。語源的にはcrisis、clime、discriminate、shearと同じ。

certain

certain: [13] Certain comes ultimately from Latin certus ‘sure, fixed’, which derived from the past participle of the verb cernere ‘decide’. The Latin adjective was extended in Vulgar Latin to *certānus, which passed into English via Old French certain. Other English words based on certus include certify [14] (from late Latin certificāre) and its derivative certificate, and certitude [15] (from late Latin certitūdō).
=> crime, crisis, decree, discern, discrete, discriminate, excrement, riddle, secret

certain (adj.)

c. 1300, "determined, fixed," from Old French certain "reliable, sure, assured" (12c.), from Vulgar Latin *certanus, from Latin certus "sure, fixed, settled, determined" (also source of Italian certo, Spanish cierto), originally a variant past participle of cernere "to distinguish, decide," literally "to sift, separate" (see crisis).

Of persons, "full of confidence in one's knowledge or judgment," from mid-14c. Euphemistic use (of a certain age, etc.) attested from mid-18c. Certainer, certainest were common to c. 1750, but have fallen from proper use for some reason. Expression for certain "assuredly" is attested by early 14c.

1. There is a certain impatience among some of the soldiers.

少しいらいらしている兵士がいます。

2.Over the years he 's demonstrated a certain prescience in foreign affairs.

ここ数年来、外交事務の面で一定の予見性を示してきた。

3.I feel certain that it will all turn out well.

最後はきっと喜ぶと思います。

4.There are certain things he does that drive me mad.

彼のある行動に私は腹が立った。

5.Parents can programme the machine not to turn on at certain times.

親は、このマシンのプログラムを特定の時間帯にオープンできないように設定できます。