Definition of gamma
noun
the third letter of the Greek alphabet (Γ, γ), transliterated as ‘g.’. - The combinations γγ, γκ, and γχ are usually transliterated as ‘ng,’ ‘nc’ or ‘nk,’ and ‘nch’ or ‘nkh’
[as modifier] denoting the third in a series of items, categories, etc.. [as modifier] relating to gamma rays:gamma detector (
Gamma)
[followed by Latin genitive] Astronomy the third (usually third-brightest) star in a constellation:Gamma Orionis Physics (plural same) a unit of magnetic field strength equal to 105 oersted.