Bible prophecies

[orangebox21]

What's the definition of generation in this context?
I'm asking because without a good definition the prophesy is basically meaningless.

Full Definition Here

The original word for "this generation" is genea. Strong's concordance for this shows:

1) fathered, birth, nativity
2) that which has been begotten, men of the same stock, a family
a) the several ranks of natural descent, the successive members of a
genealogy
b) metaph. a group of men very like each other in endowments, pursuits,
character
1) esp. in a bad sense, a perverse nation
3) the whole multitude of men living at the same time
4) an age (i.e. the time ordinarily occupied be each successive generation), a
space of 30 - 33 years