adnation
/adˈneɪʃn/ /ədˈneɪʃn/Botany
noun
Attachment of the surface of one part to that of another part; the condition of being adnate; especially the union of one whorl of floral organs to another dissimilar whorl, as stamens to petals.
Origin
Mid 19th century; earliest use found in Asa Gray (1810–1888), botanist. From adnate + -ion; compare -ation.