acumination
/əˌkjuːmɪˈneɪʃn/noun
1A pointed or tapering part; (Mineralogy ) †a part of a crystal regarded as notionally resulting from acumination ( obsolete ). Now chiefly Botany and Zoology.
2The action of giving a point to something or bringing something to a point (chiefly figurative ); ( Mineralogy ) †the notional replacement of an angle or plane of a crystal by three or more planes meeting in a point ( obsolete ).
Origin
Mid 17th century. From post-classical Latin acumination-, acuminatio action of sharpening, sharpness, pointedness from acuminat-, past participial stem of acuminare to sharpen + classical Latin -iō.