nucleal
/ˈnjuːklɪəl/adjective
1Central in importance; pivotal, seminal.
2 Biology. Designating Feulgen's method for staining material in the nuclei of cells, or the reaction on which it is based.
Origin
Early 19th century; earliest use found in Samuel Taylor Coleridge (1772–1834), poet, critic, and philosopher. From nucleus + -al. Compare nuclear.