IPA: /prɪˈzjuːmɪdli/
KK: /prɪˈzumɪdli/
In a manner that is assumed to be true or likely based on available information.
Presumedly, the meeting will start at 10 AM, as it usually does.
Presumedly → It is formed from "presume" (from Latin "praesumere", meaning to take for granted or suppose) and the adverbial suffix "-ly" (meaning in a manner of). The word "presumedly" means in a manner that is taken for granted or supposed.
Think of 'presume' as taking something for granted, and remember that 'presumedly' means doing so in a certain manner.