Cos·tel·lo 
(kŏs-tĕlō), John Aloysius 1891-1976.
(kŏs-tĕlō), John Aloysius 1891-1976. Irish prime minister (1948-1951 and 1954-1957) who took Ireland out of the Commonwealth of Nations (1949).
- hydrogen
- hydrogenase
- hydrogenate
- hydrogen bomb
- hydrogen bond
- hydrogen bromide
- hydrogen chloride
- hydrogen cyanide
- hydrogen fluoride
- hydrogen iodide
- hydrogen ion
- hydrogenolysis
- hydrogenous
- hydrogen peroxide
- hydrogen sulfide
- hydrogeologic
- hydrogeological
- hydrogeologist
- hydrogeology
- hydrographer
- hydrographic
- hydrographically
- hydrography
- hydroid
- hydrokinetic