Definition from Wiktionary, the free dictionary
|wrong side out or up; anti-||feed|
|simp. and trad.
- originally referred to a raven (trad. 烏鴉, simpl. 乌鸦) that would provide food to its mother after becoming an adult
- to take care of one's parents when they are old
- to give back to a person or institution which has contributed to one's own growth