(indicating it is too late for something, or some point of no return has been passed) this late, after such a long time

dawn of a new age

time of creation

school term, trimester semester

adolescence (period between childhood and maturity)

heyday, prime, height

irregular, occasional, unscheduled

irregularity

(slang, fiction) cold period of tsundere

デレ期: (slang, fiction) lovey-dovey period of tsundere / デレ期, dr期: (idol fandom) period of infatuation with an idol