from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
RELATIVE POWERS. Those which relate to land, so called to distinguish them
from those which are collateral to it.
2. These powers are appendant, as where a tenant for life has a power
of making leases in possession. They are in gross when a person has an
estate in the land, with a power of appointment, the execution of which
falls out of the compass of his estate, but, notwithstanding, is annexed in
privity to it, and takes effect in the appointee out of an interest
appointed in the appointer. 2 Bouv. Inst. n. 1930.