1. Toward the source or against the current
   - upstream

Antonym: downriver

• Aplysiidae
• apnea
• apneic
• apnoea
• apnoeic
• apoapsis
• apocalypse
• apocalyptic
• apocalyptical
• apocarpous
• apocenter
• apocentre
• apochromatic
• apocope
• apocrine
• apocrine gland
• Apocrypha
• apocryphal
• apocryphally
• Apocynaceae
• apocynaceous
• Apocynum
• Apocynum androsaemifolium
• Apocynum cannabinum
• Apocynum pumilum