Impregnation or fertilization of an animal by the external contact of genital orifices, without intromission. Also: †fertilization of plants by pollination (obsolete). Also figurative and in extended use: mouth-to-mouth kissing.
Late 17th century; earliest use found in Nehemiah Grew (a1641–1712), botanist and physician. From post-classical Latin adosculat-, past participial stem of adosculari to keep on kissing + -ion.