(b) Definitions.— In this section Federal correctional institution means any Federal prison, Federal correctional facility, Federal community program center, or Federal halfway house. murder means a first degree or second degree murder (as defined in section
1111). term of life imprisonment means a sentence for the term of natural life, a sentence commuted to natural life, an indeterminate term of a minimum of at least fifteen years and a maximum of life, or an unexecuted sentence of death.