hairy cell leukemia a form of chronic leukemia marked by splenomegaly and by an abundance of abnormal large mononuclear cells covered by hairlike villi (hairy cells) in the bone marrow, spleen, liver, and peripheral blood.
A set of orbitals are said to be degenerate if they all have the same energy. This degeneracy can sometimes be lifted by external electric or magnetic fields.
Degenerate simply means having the same energy. The word is borrowed from mathematics, where it describes, for example, a quadratic equation whose two roots are equal to each other. For example, in an atom, the 2p orbitals are 3-fold degenerate. Valence electrons are not always degenerate with each other.