IPA: /məˈlɛkjələrli/
KK: /məˈlɛkjələrli/
In a way that relates to molecules, which are the smallest units of a chemical compound.
The substance behaves molecularly, showing properties that depend on its molecular structure.
Molecularly → It is formed from "molecule" (from Latin *molecula*, meaning a small mass or particle) and the suffix "-ly" (meaning in a manner of). The word "molecularly" refers to something that is done in a manner relating to molecules or at the molecular level.
Think of 'molecule' as a small particle, and remember that 'molecularly' means relating to or in the manner of these small particles.