1. Very occasionally

Encyclopedia: Once in a blue moon

• avoidable
• avoidance
• avoider
• avoirdupois
• avoirdupois unit
• avoirdupois weight
• Avon
• avouch
• avouchment
• avow
• avowal
• avowed
• avowedly
• avower
• avulse
• avulsion
• avuncular
• aw
• aw sucks!
• await
• awaited
• awake
• awaken
• awakened
• awakening