IPA: /məˈtɪəriəli/
KK: /məˈtɪr.i.əl.i/
To a significant extent or degree; in a way that is important or substantial.
The changes in the policy will materially affect the company's profits.
Materially → It is formed from "material" (from Latin "materialis", meaning pertaining to matter) and the suffix "-ly" (meaning in a manner of). The word "materially" means in a manner that relates to physical matter or substance.
Think of 'material' as relating to 'matter' — so when something is done 'materially', it is done in a way that pertains to physical substance.