instant

• adj.即座に；緊急に；差し迫った
• n. 瞬間的な; 即時の; 一瞬の

つまり、近くに立つ、緊急にスタンバイする、後の派生語immediate。

instant

instant: [15] Latin instāre meant ‘be present’ (it was a compound verb formed from the prefix in- ‘upon’ and stāre ‘stand’). Its present participle instāns was used adjectivally for ‘present’, and hence by extension for ‘urgent’. The latter was actually the meaning originally taken up by English, but it has now virtually died out. ‘Present’ was introduced in the mid-16th century (it now survives in the abbreviation inst, used in giving dates to signify ‘the present month’), and by the end of the century this had evolved into the main current sense ‘immediate’.

The noun instant ‘moment’ comes from medieval Latin tempus instāns ‘present time’. Derived from instāns was the Latin noun instantia ‘presence, urgency’. Again it was the latter that originally came into English with instance [14]. The main modern sense ‘example’, first recorded in the 16th century, appears to come ultimately from a semantic progression in medieval Latin from ‘urgency’ to ‘eager solicitation’ and hence to ‘legal pleading’.

Further metaphoricization took it on to ‘new argument or example adduced to counter a previous one’, and hence in due course to simply ‘example’.
=> instance, stand, station, statue

instant (n.)

late 14c., "infinitely short space of time," from Old French instant (adj.) "assiduous, at hand," from Medieval Latin instantem (nominative instans), in classical Latin "present, pressing, urgent," literally "standing near," present participle of instare "to urge, to stand near, be present (to urge one's case)," from in- "in" (see in- (2)) + stare "to stand," from PIE root *sta- "to stand" (see stet). Elliptical use of the French adjective as a noun.

instant (adj.)

mid-15c., "present, urgent," from Old French instant (14c.), from Latin instantem (nominative instans) "pressing, urgent," literally "standing near" (see instant (n.)). Meaning "now, present" is from 1540s, and led to the use of the word in dating of correspondence, in reference to the current month, often abbreviated inst. and persisting at least into the mid-19c. Thus 16th inst. means "sixteenth of the current month." Sense of "immediately" is from 1590s. Of foods, by 1912. Televised sports instant replay attested by 1965. Instant messaging attested by 1994.

1. In the same instant he flung open the car door.

それと同時に、彼はドアを強く押した。

2.I had bolted the door the instant I had seen the bat.

コウモリを見るとドアをラッチしました。

3.At that instant the museum was plunged into tal darkness.

その時、博物館は真っ暗になった。

4.He smiled back，which for an instant transfigured his unrevealing features.

彼は笑った。その瞬間、じっとしていた顔に艶が出た。

5.With a glazed stare she revived for one last instant .

彼女は最後にしばらく目を覚まし、目がぼんやりしていた。