terce
/təːs
/noun
A service forming part of the Divine Office of the Western Christian Church, traditionally said (or chanted) at the third hour of the day (i.e. 9 a.m.).The Order of Service for Noonday may be used (with appropriate choices from the options for lessons and collects) for terce, sext, or none.
Origin
Late Middle English: from Old French, from Latin tertia, feminine of tertius 'third'. Compare with tierce.