定于

set at / scheduled at

to set / to fix / to determine / to decide / to order

to go / to take / sentence-final interrogative particle / variant of 於|于[yu2]

(of time or place) in; at; on / (indicating any indirect relation) to; toward; vis-à-vis; with regard to; for / (indicating a source) from; out of / (used in comparison) than / (used in the passive voice) by

(idiom) to rely on a single authority to determine what is correct / to regard a source (or entity or individual) as the ultimate authority