IPA: /ɪkˈstɛndɪdli/
KK: /ɪkˈstɛndɪdli/
In a way that is prolonged or stretched out over time or space.
The meeting was extendedly long, lasting for over three hours.
Extendedly → It is formed from "extend" (from Latin "extendere", meaning to stretch out) and "-ly" (a suffix used to form adverbs). The word "extendedly" means in a manner that stretches out or is prolonged.
Think of 'stretching out' ('extend') to remember that 'extendedly' means doing something in a prolonged or stretched manner.