A Sheliak colony ship was a type of starship used by the reclusive Sheliak species for the transport of "the membership", which was their term for "colonists".
In 2366 one such ship was about to arive at Tau Cygna V, leading the Sheliak to request the removal of a Human colony on Tau Cygna V. This represented the first contact between the Federation and Sheliak in 111 years. The USS Enterprise-D intercepted the ship. Asking for a consultation under the Treaty of Armens, Jean-Luc Picard and Deanna Troi boarded the ship to discuss with the commander about getting more time. Viewing Picard's response to its refusal as an emotional outburst, Picard and Troi were beamed back to the Enterprise. The commander finally relented when Picard used the treaty to delay them, and it waited three weeks to continue to Tau Cygna V. (TNG: "The Ensigns of Command")