Balmer series Reference Libraries
H II Region -- An H II region is an emission nebula associated with hot, young, blue stars, and star forming regions. H II, or singly-ionized hydrogen, is nebular gas ionized by ultraviolet light emitted by these hot, young stars of spectral type O and B. The sizes of H II regions are determined both by the amount of gas present, and by the luminosity of the O and B stars -- the more...
- Small missiles, especially grape, canister, fragments of iron, and the like, when fired, as upon an enemy at close quarters.
- To fire mitraille at.