bohr theory: (physics) a theory of atomic structure that combined Rutherford's model with the quantum theory; electrons orbiting a nucleus can only be in certain stationary energy states and light is emitted when electrons jump from one energy state to another
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
terrorist: a radical who employs terror as a political weapon; usually organizes with other terrorists in small cells; often uses religion as a cover for terrorist activities