1. A paper from the custom house in certificate of the nature of the cargo of a ship when liable to be searched in time of war.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• aea letter,
• zea letter,
• xea letter,
• eea letter,
• wea letter,
• swa letter,
• ssa letter,
• sda letter,
• sra letter,
• s4a letter,
• s3a letter,
• sez letter,
• ses letter,
• sew letter,
• seq letter,
• sea ketter,
• sea petter,
• sea oetter,
• sea lwtter,
• sea lstter

The adjective form of "Sea letter" is "seafaring".

The plural form of "sea letter" is "sea letters".

The singular form of the word "Sea letter" is "Seal letter".