sequester (vb.) ; sequestrate
Generally, sequestrate means nothing that sequester, the more common term, does not also mean. Both terms are old: sequester dates from the 14th century, sequestrate from the early 16th century. In law, sequester = to remove (as property) from the possession of the owner temporarily; to seize and hold the effects of a debtor until the claims of creditors are satisfied (OED). The lay meaning of the term, of course, is “to set aside, separate,” as to sequester (or separate) the jury.
Sequestrate is given two slightly different senses by the OED, in addition to the overlapping senses: (1) “to divert the income of an estate or benefice, temporarily or permanently, from its owner into other hands”; and (2) (in Scots law) “to place … lands belonging to a bankrupt, or [those] of disputed ownership, … in the hands of a judicial trustee, for the prevention of waste.” These two senses are rare, however, and—except in Scotland—it is best to avoid sequestrate as a
The sole weakness of this advice is that the agent noun is sequestrator and not, ordinarily, sequesterer.
Often no such nuance was intended, and sequester is the better word—e.g.:
“The practice of sequestrating [read sequestering] the property of the defendant to coerce his obedience to the decree was soon developed.”
Henry Lacey McClintock, Handbook of Equity 22 (1936).
“It is difficult to see why a plaintiff in any action for a personal judgment in tort or contract may not … apply to the chancellor for a so-called injunction sequestrating [read sequestering] his opponent's assets pending recovery and satisfaction of a judgment in such a law action.” De Beers Consol. Mines v. U.S., 325 U.S. 212, 222–23 (1945) (per Roberts, J.).