IPA: /ʌˈpɛnd/
KK: /ʌˈpɛnd/
To be turned upside down or overturned.
The boat began to upend in the rough waters.
Past: upended
Past Participle: upended
To turn something upside down or to completely change its position or state.
The strong wind upended the table, sending everything on it crashing to the ground.
Past: upended
Past Participle: upended
Upend is formed from "up" (meaning to a higher position) and "end" (meaning the final part of something). The word "upend" means to turn something upside down or to overturn it, placing the end in an upward position.
Think of turning something 'up' so that its 'end' is now on top — that's what upend means.