A depository is a securities-market institution that maintains an authoritative ledger of investors' positions, often through accounts operated by intermediaries, and supports the administration of book-entry ownership and transfers. It may additionally provide services for managing issuer or shareholder registers. This role differs from that of a custodian, whose principal responsibility is protecting and administering assets entrusted by clients.
Source: European Central Bank (ECB) (source). This glossary entry is an independently worded adaptation of the cited information.