one of the main longitudinal beams (or plates) of the hull of a vessel; can extend vertically into the water to provide lateral stability | long thick piece of wood or metal or concrete, etc., used in construction |
the median ridge on the breastbone of birds that fly | a gymnastic apparatus used by women gymnasts |
a projection or ridge that suggests a keel | the broad side of a ship |
| (nautical) breadth amidships |
| a signal transmitted along a narrow path; guides airplane pilots in darkness or bad weather |
| a column of light (as from a beacon) |
| a group of nearly parallel lines of electromagnetic radiation |