1. Occurring every six months or during every period of six months
   - semestrial

See also: periodic, periodical, semester

• arrant
• arras
• array
• arrayed
• arrear
• arrearage
• arrears
• arrest
• arrest warrant
• arrested development
• arrestee
• arrester
• arrester hook
• arresting
• arrestment
• Arrhenatherum
• Arrhenatherum elatius
• Arrhenius
• Arrhenius theory of dissociation
• arrhythmia
• arrhythmic
• arrhythmical
• arris
• arrival
• arrival gate