1. Having the wind against the forward side of the sails
   "the ship came up into the wind with all yards aback"
    
2. By surprise
   "taken aback by the caustic remarks"

Encyclopedia: Aback

• Casmerodius albus
• Caspar
• Caspar Bartholin
• caspase
• caspase-mediated cell death
• Casper
• Caspian
• Caspian Sea
• casque
• casquet
• casquetel
• Cass Gilbert
• Cassandra
• cassareep
• cassation
• cassava
• cassava starch
• Cassegrainian telescope
• casserole
• cassette
• cassette deck
• cassette player
• cassette recorder
• cassette tape
• cassia