U18 or U-18 may refer to:
* , various vessels
*
Ryan U-18 Navion, an American utility aircraft
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Small nucleolar RNA SNORD18
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Small rhombihexahedron
In geometry, the small rhombihexahedron (or small rhombicube) is a nonconvex uniform polyhedron, indexed as U18. It has 18 faces (12 squares and 6 octagons), 48 edges, and 24 vertices. Its vertex figure is an antiparallelogram.
Related polyhedra ...
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U-18 self-propelled gun, a Soviet experimental self-propelled gun
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Under-18 athletics
Youth is a category of athletics in which athletes compete under the age of 18 years. Countries all around the world compete in athletics. World Youth Athletics Competitions are held every 2 years which contain the best Youth competitors in the ...
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