IPA: /ˈɡrændli/
KK: /ɡrændli/
In a way that is impressive and shows great importance or style.
The ceremony was held grandly, with beautiful decorations and elegant music.
Grandly → It is formed from "grand" (from Old French *grand*, meaning large or great) and "-ly" (meaning in a manner of). The word "grandly" means in a manner that is large or great, often implying magnificence or splendor.
Think of something being done in a 'great' way — 'grand' means large or impressive, and '-ly' indicates the manner of doing it.