blue*
Here are some words that match your criteria:

- blue
- blue African lily
- blue air
- blue angel
- blue ash
- blue baby
- blue blood
- blue book
- blue bugle
- blue bull
- blue cardinal flower
- blue cat
- blue catfish
- blue channel cat
- blue channel catfish
- blue cheese
- blue cheese dressing
- blue chip
- blue cohosh
- blue columbine
- blue copperas
- blue crab
- blue curls
- blue daisy
- blue darter
- blue devil
- blue devils
- blue elder
- blue elderberry
- blue false indigo
- blue fig
- blue flag
- blue fleabane
- blue fox
- blue funk
- blue goose
- blue grama
- blue grass
- blue gum
- blue jack
- blue jasmine
- blue jay
- blue jean
- blue jessamine
- blue jets
- blue joke
- blue law
- blue lotus
- blue mahoe
- blue marguerite
- blue marlin
- blue mockingbird
- blue mold fungus
- blue moon
- Blue Mountain tea
- blue murder
- Blue Nile
- blue note
- blue orchid
- blue pea
- blue peafowl
- blue peter
- blue pickerel
- blue pike
- blue pikeperch
- blue pimpernel
- blue point
- blue point Siamese
- blue pointed
- blue poppy
- blue racer
- blue ribbon
- blue ribbon commission
- blue ribbon committee
- blue ribbon jury
- Blue Ridge
- Blue Ridge Mountains
- blue runner
- blue sage
- blue shark
- blue skullcap
- blue sky
- blue sky law
- blue star
- blue stem
- blue stone
- blue story
- blue succory
- blue thistle
- blue tit
- blue toadflax
- blue tulip
- blue vitriol
- blue wall
- blue wall of silence
- blue walleye
- blue whale
- blue-belly
- blue-black
- blue-blind