bivalent /bī-vāˈlənt or bivˈə-lənt/

1. Having a valency of two (chem)
2. Relating to one of a pair of homologous chromosomes (also noun)

• surface-to-surface
• surface-vessel
• surface-vessels
• surface water
• surface wind
• surface winds
• surface worker
• surface workers
• surfacing
• surfacings
• surfactant
• surfactants
• surf-bather
• surf-bathers
• surf-bathing
• surfbird
• surfbirds
• surfboard
• surfboarding
• surfboards
• surf boat
• surf boats
• surf canoe
• surf canoes
• surfcaster