IPA: /ˈræptli/
KK: /ræptli/
In a way that shows great interest or attention, often with a sense of being completely absorbed or captivated.
The audience listened raptly to the speaker, hanging on every word.
Raptly → It is formed from "rapt" (from Latin "rapere", meaning to seize or carry away) and the adverbial suffix "-ly" (meaning in a manner of). The word "raptly" means in a manner that is seized or carried away, often referring to being engrossed or absorbed in something.
Think of being so absorbed in something that it feels like you are 'carried away' ('rapere') by it — that's why you are raptly focused.