Definition
In maritime law, the officer second in rank to the master on board a merchant vessel. The mate assists the master in navigating and managing the ship and, upon the master's death or absence, succeeds by virtue of office to command of the vessel — assuming the duties of master without ceasing to hold the rank of mate. When used without qualification, "mate" refers to the first mate. Larger vessels may carry a second, third, or fourth mate, each designated accordingly.
Common Language
Modern common usage (Wiktionary): A clipping of "checkmate"; also used informally to mean a friend or companion (chiefly British/Australian).
Historical common usage (Webster's 1913): The Paraguay tea, dried leaf of the Brazilian holly (Ilex Paraguensis), steeped as a beverage common in South America.
Neither common meaning bears any relation to the legal term. A researcher encountering "mate" in a maritime legal document should not read it as an informal title or social designation — it is a formal officer's rank with defined legal duties and succession rights aboard a merchant vessel.
Common Confusion
"Mate" in legal sources should not be confused with its occasional appearance in older texts referring to a subordinate or deputy in non-maritime contexts. Rapalje & Lawrence's entry under this headword appears to have been corrupted or misassigned in transmission, containing text belonging to a separate entry (likely "material" or "misrepresentation") with no coherent definition of the maritime officer. Researchers relying on Rapalje & Lawrence for this term should treat that entry as unusable and consult Bouvier or Burrill instead.
Why It Matters in Research
The legal significance of this term arises almost entirely in admiralty and maritime law contexts. Researchers working in that corpus should be alert to several points:
First, succession of command is the term's most legally consequential dimension. Burrill's formulation — that the mate succeeds virtute officii (by virtue of office) to the master's duties — carries weight in cases involving contracts executed at sea, liability during a voyage, and the legal authority of acts performed while the mate is acting as master. This distinction matters for interpreting historical shipping documents and crew agreements.
Second, the term appears in insurance and shipping cases as a factor in establishing vessel hierarchy and responsibility. Whether a particular officer qualified as "mate" could affect questions of agency, negligence, and contractual authority.
Third, "mate" appears in statutes and regulations governing merchant marine licensing and certification. Its meaning in regulatory sources is more precisely defined than in the common law cases and may vary by era and jurisdiction. Nineteenth-century sources use the term descriptively; twentieth-century regulatory regimes assign it formal credentialing requirements.
Fourth, researchers should note that the term is almost exclusively a merchant vessel term. Naval usage employs different rank structures and terminology; "mate" in a naval context (e.g., boatswain's mate) carries a different meaning and should not be read against the maritime law definition.
Historical Dictionary Support
The historical dictionaries are in broad agreement on the core definition: the mate is the officer next in rank to the master on a merchant vessel. Black's (both editions) states this succinctly. Bouvier expands usefully on the rank structure, clarifying that "mate" without qualification means the first mate and that vessels may carry multiple mates depending on size and trade. Burrill adds the most legally substantive language, explaining the succession principle and citing Kent's Commentaries for the proposition that the mate does not lose his rank when acting as master — he absorbs the master's duties cumulatively.
Anderson's entry is a cross-reference only (directing to MARINER and SHIP), contributing nothing substantive. Rapalje & Lawrence's entry is, as noted above, garbled and unreliable for this headword.
The historical sources share a common gap: none addresses the mate's duties or authority with much precision. They establish rank and succession but say little about specific legal responsibilities — cargo oversight, log-keeping obligations, treatment of crew — that appeared in contemporaneous case law and statutory sources. Researchers needing that level of detail should move beyond the dictionaries to maritime treatises and admiralty case reporters.
Jurisdictional Note
The core definition is drawn from general admiralty law and is consistent across common law jurisdictions. U.S. federal admiralty jurisdiction governs most questions involving the mate's legal status aboard American merchant vessels. British maritime law shaped the early American understanding, and the English treatises cited in the historical dictionaries (Maude & Pollock on Merchant Shipping, Kent's Commentaries) remain reference points for nineteenth-century American cases.