Gamma Delta Iota (ΓΔΙ) or God Damn Independent; a fictitious fraternity used by fraternity and sorority members to refer to people not affiliated with such organizations.

(computing, Microsoft, Microsoft Windows) Initialism of Graphics Device Interface.. / (automotive) Initialism of gasoline direct injection. (fuel injection)

(euphemistic, slang, rare) Abbreviation of goddamn it.

plural of GDI

(computing, Microsoft Windows) A newer and improved version of GDI written in C++.