Attributive and in the genitive. Designating theories and concepts arising from Milankovitch's study of the earth's climate; "Milankovitch cycle" noun any of three cyclic variations in the orbit of the earth around the sun (involving respectively the eccentricity of the orbit, the obliquity of the earth's axis, and the precession of the equinoxes) which in the Milankovitch theory are associated with cyclic changes in the earth's climate. "Milankovitch theory" noun a theory connecting climate changes and glaciations with cyclic variations in the earth's orbit (the Milankovitch cycles).
1930s; earliest use found in Geological Magazine. From the name of Milutin Milanković, Serbian mathematician, astronomer, and geophysicist, who published theories on climate change (including Théorie Math. des Phénomènes Thermiques and Kanon der Erdbestrahlung).