ice·boat 
(īsbōt′)
(īsbōt′)n.
1. A boatlike vehicle set on sharp runners, used for sailing on ice.
2. See icebreaker.
iceboat′er n.
iceboat′ing n.
- understeer
- understood
- understory
- understratum
- understudy
- undersubscribed
- undersupply
- undersurface
- undertake
- undertaker
- undertaking
- under the circumstances
- under the counter
- under-the-counter
- under the gun
- under the hammer
- under the influence
- under the knife
- under the rose
- under the skin
- under the sun
- under the table
- under-the-table
- under the weather
- under the wind