sex·en·ni·al 
(sĕk-sĕnē-əl)
(sĕk-sĕnē-əl)adj.
1. Occurring every six years.
2. Relating to or lasting six years.
n.
An event that occurs every six years.
[From Latin sexennium, of six years : sex, six; see SEX- + annus, year; see at- in the Appendix of Indo-European roots.]
sex·enni·al·ly adv.
- Catch-22
- catchable
- catch a crab
- catchall
- catch-as-catch-can
- catch basin
- catch breath
- catch death
- catcher
- catch fire
- catchfly
- catchiness
- catching
- catch it
- catchment
- catchment area
- catch on
- catch (one's) breath
- catch one's breath
- catch (one's) death
- catch one's death
- catch out
- catchpenny
- catch phrase
- catchpole