Triduum
Liturgical seasons
Pre-Christmas
Advent
(
Western
)
Nativity Fast
(
Byzantine
)
Annunciation
(
Syriac
)
Christmas
Epiphany
Ordinary Time
(
Western
)
Pre-Lent
Lent
(
Western
)
/
Great Lent
(
Eastern
)
Paschal Triduum
(
Western
)
Easter
Pentecost
Ordinary Time
(
Western
)
Summer
(
East Syriac
)
Apostles' Fast
(
Eastern
)
Dormition Fast
(
Eastern
)
Elijah–Cross–Moses (
East Syriac
)
Dedication of the Church (
Syriac
)
A
triduum
(
/
ˈ
t
r
ɪ
d
.
j
u
ə
m
,
ˈ
t
r
ɪ
dʒ
u
ə
m
/
;
pl.
tridua
) is a religious observance that lasts three days.