Noun
(uncountable) The act or process of making something more complex.
(countable, mathematics) An extension from a basis on real numbers to a basis on complex numbers.
Source: en.wiktionary.orgA new level of organization means a simplification of system function, and of the corresponding system structure, it also means the initiation of a process of progressive structural and functional complexification. Ervin László
Hermitian vector spaces and spinors If the vector space V has extra structure that provides a decomposition of its complexification into two maximal isotropic subspaces, then the definition of spinors (by either method) becomes natural. Source: Internet
Finally, the complexification of human cultures, particularly language, facilitated a quickening of evolution in which cultural evolution occurs more rapidly than biological evolution. Source: Internet