1. Set apart, withdraw from company or ordinary use, place in isolation for protection, privacy, or concealment. Sequester implies purposeful separation, an act with policy or principle behind it.

2. Confiscate or take legal possession of property, funds, or goods; hold in custody by authority (legal).

From Latin sequestrare, from sequester "trustee, depositary," one who holds something in safekeeping between parties. Apartness as stewardship.