cedra gismu

x1 is an era/epoch/age characterized by x2 (event/property/interval/idea).

(x2 interval should be the defining boundaries; if merely a characterizing period, the nature of the interval should be expressed in an abstract bridi, or the interval should be marked with tu'a; x2 may also be characteristic object(s) or practices of the era, if marked with tu'a); See also ranji, temci, citsi.

In notes:

citsi
x1 is a season/is seasonal [cyclical interval], defined by interval/property x2, of year(s) x3.
ranji
x1 (event/state) continues/persists over interval x2; x1 (property - ka) is continuous over x2.
temci
x1 is the time-duration/interval/period/[elapsed time] from time/event x2 to time/event x3.
cimnytei
t1=c1 is an eternity.
clatei
t1 is a long time/duration/interval/period/elapsed time from time/event t2 to time/event t3.
ctona'a
x1 is x2 centuries in duration by standard x3.
vercedra
c1 is the childhood (time of being a child) of v1.
ditcu
x1 is the time-duration/interval/period/[elapsed time] of event x2.
ca'arxe
x1 is modern in aspect x2
cabrxe
x1 is modern in aspect x2