Definition of theta
noun
the eighth letter of the Greek alphabet (Θ, θ), transliterated as ‘th.’. (
Theta)
[followed by Latin genitive] Astronomy the eighth star in a constellation:Theta Draconis [as modifier] Chemistry denoting a temperature at which a polymer solution behaves ideally as regards its osmotic pressure. [as modifier] denoting electrical activity observed in the brain under certain conditions, consisting of oscillations having a frequency of 4 to 7 hertz:theta rhythm
symbol
(
θ)
temperature (especially in degrees Celsius). (
θ)
a polar coordinate. Often coupled with phi.
