“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.