1) source, origin
1a) a book of one's lineage, i.e. in which his ancestry or progeny are enumerated
2) used of birth, nativity
3) of that which follows origin, viz. existence, life
3a) the wheel of life (Jam 3:6), other explain it, the wheel of human origin which as soon as men are born begins to run, i.e. its course of life
Part of Speech: noun feminine
Citing in TDNT: 1:682, 117
From the same as G1074; nativity; figuratively nature: - generation, nature (-ral).
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root γένεσις; click on the second column to search for that grammatical form of the root γένεσις; click on the third column to search for that word and grammatical form; click on the total to search for the root γένεσις.