a major feastday of the Roman Catholic Church on which Catholics are bound to attend Mass and refrain from servile work
holy day of obligation in American English
noun
1.
a day on which Roman Catholics are duty-bound to attend Mass and abstain from certain kinds of work
2.
a day on which Episcopalians are expected to take communion
Word origin
[1930–35]This word is first recorded in the period 1930–35. Other words that entered Englishat around the same time include: acoustic phonetics, hypercorrection, preset, saddle stitch, technical foul