1. Occurring every third year or lasting 3 years

1. The 300th anniversary (or the celebration of it)
   - tercentennial, tercentenary

Derived forms: triennials

See also: periodic, periodical

Type of: anniversary, day of remembrance

Encyclopedia: Triennial

• photographer's model
• photographic
• photographic camera
• photographic density
• photographic emulsion
• photographic equipment
• photographic film
• photographic material
• photographic paper
• photographic plate
• photographic print
• photographically
• photography
• photogravure
• photojournalism
• photojournalist
• photolithograph
• photolithography
• photoluminescence
• photolysis
• photomechanical
• photomechanics
• photometer
• photometric
• photometrical