The important noun ημερα (emera) means day

The important noun ημερα (emera) means day, and survives in modern English in such useful words as hemeralopia (day blindness), hemerobaptist, (someone from a Jewish sect which practiced daily ritual bathing) and hemerocallis (a lily that flowers for one mere day).

Where our word comes from isn't immediately clear but the word ημι (hemi), meaning half (hence our word hemisphere) certainly jumps to mind, specifically when we remember Jesus saying that there are twelve hours in a day (John 11:9), which is obviously half of the twenty-four we moderns are used to. That's because, unlike our English word "day", the Greek word ημερα (emera) is solely reserved for the lit half of earth's solar day, and particularly the goings on of a day (Matthew 6:34, Luke 1:23, Romans 14:5). Our word ημερα (emera) is often used juxtaposed to νυξ (nux), meaning night, or the period without legitimate activity (hence our word nocturnal; Matthew 4:2), and the two are creatively combined into the word νυχθημερον (nuchthemeron), or "night 'n-day", which covers the whole twenty-four hour cycle (see below).

Rather than exclusively denoting a stretch of clock-time of fixed length, our word ημερα (emera) may in a poetic sense denote any continual period during which legitimate activity is performed without interruption. As such our word ημερα (emera) means "uninterrupted procedure" or "routine" and may be used synonymously with "trial/hearing/test" (Acts 17:31, 1 Corinthians 4:3, 3:13). Hence Jesus submitted that he had been in the temple daily, or the whole time, while the evil of darkness continued nightly, also the whole time (Luke 22:53).

On the "the day of John's public appearance to Israel" (Luke 1:80), John may have showed up first but his initial showing up was the beginning of continued public activity. The "day of slaughter" (James 5:5), likewise, may not be associated with one particular calendar day and will probably also not last precisely twelve hours, but denotes an indefinite period of uninterrupted carnage. The same goes for the "day of judgment" (Matthew 10:5), the "day of redemption" (Ephesians 4:30), the "day of wrath and revelation" (Romans 2:5), and the "day of the Lord" (Matthew 7:22, Luke 17:24, Acts 2:20, 2 Peter 3:12). Likewise the "last day", upon which all mankind resurrects, is probably not a calendar day after which the earth stops spinning, but the final procedure before the new creation can commence (John 6:39-40).

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