A typical concordance will illustrate that yom can have a range of meanings: a period of light as contrasted to night, a 24-hour period, time, a specific point of time, or a year.
A classic, well-respected Hebrew-English lexicon8 (a dictionary) has seven headings and many subheadings for the meaning of yom—but it defines the creation days of Genesis 1 as ordinary days under the heading “day as defined by evening and morning.”
A number and the phrase “evening and morning” are used with each of the six days of creation (Gen. 1:5, 8, 13, 19, 23, 31).
Outside Genesis 1, yom is used with a number 359 times, and each time it means an ordinary day.9 Why would Genesis 1 be the exception?10
Outside Genesis 1, yom is used with the word “evening” or “morning”11 23 times. “Evening” and “morning” appear in association, but without yom, 38 times. All 61 times the text refers to an ordinary day. Why would Genesis 1 be the exception?12
In Genesis 1:5, yom occurs in context with the word “night.” Outside of Genesis 1, “night” is used with yom 53 times, and each time it means an ordinary day. Why would Genesis 1 be the exception? Even the usage of the word “light” with yom in this passage determines the meaning as ordinary day.13
The plural of yom, which does not appear in Genesis 1, can be used to communicate a longer time period, such as “in those days.”14 Adding a number here would be nonsensical. Clearly, in Exodus 20:11, where a number is used with “days,” it unambiguously refers to six earth-rotation days.
There are words in biblical Hebrew (such as olam or qedem) that are very suitable for communicating long periods of time, or indefinite time, but none of these words are used in Genesis 1.15 Alternatively, the days or years could have been compared with grains of sand if long periods were meant.
http://www.answersingenesis.org/articles/nab/could-god-have-created-in-six-days
Agqin- IF we macroevolved, then the bible is LYING to us by telling us that ‘God breathed life into the nostrils of man and woman’ and that God’ looked aroudn but found no suitible mate for Adam’ and that ‘spirit death did NOT occure BEFORE the fall’, and on and on it goes- It takes a powerful lot of twisting to make ‘yom’ mean ‘long ages’ in Genesis, as well as ignorign the articles ‘day and night’, or twistign htem to mean somethign else.
But whatever- just don’t expect us to buy ‘long ages’