Day — Yowm

• The meaning that God gave to Light / Fire was a Hebrew word that can mean a "24 hour day" (as we use the word today) or a "lighted period" of time, as seen in Psalm 91:16 "With a long life — yowm — will I satisfy him — the one who dwells in the secret place of the most High — and show him my salvation."
• One day is then defined in Genesis 1:5 with two Hebrew words:
  1.Evening — ereb — blurry time, sundown, duskiness, sweet, the basis of our word "Arab", and
  2.Morning — boqer — break forth time, sunrise, get focus and clarity, from the word "baqar" to plough, oxen and herds, enquire, scourge. A real farming word.
  In between those two words is night, darkness, midnight, the invisible moment (to humans) of darkness (and in the Exodus verses, angel of death and judgment) when no man can work.
  
• Morning at sunrise, as a word, was not used again in Genesis until Gen 19:27 and 28, when Abraham got up early in the morning and hurried to the place where he had been in the presence of the Lord, and then looking towards Sodom, he saw smoke rising as from a furnace.
  Furnace in Hebrew comes from "kabash" — "to break down / tread down in subjection", heavy stuff that came in these verses at sunrise that day. Ouch.