accessional
/əkˈsɛʃ(ə)n(ə)l/ /əkˈsɛʃən(ə)l/ /akˈsɛʃ(ə)n(ə)l/adjective
Of the nature of an increase or augmentation; additional; supplementary; accessory.
Origin
Mid 17th century; earliest use found in Thomas Browne (1605–1682), physician and author. From accession + -al.