tridecennary

English

Adjective

tridecennary (not comparable)

1. (obsolete, rare) Of or pertaining to the number thirteen
   • 1856, William Robertson, The History of the Discovery and Settlement of America:

     The order of days in every month was computed, according to him, first by what he calls a tridecennary progression of days from one to thirteen, […]

References

• OED 2nd edition 1989