Nog's pajamas
Picard in his pajamas
Pajamas or sleepwear were a type of clothing usually worn while sleeping.
Starfleet uniforms were often confused with pajamas by those who were unfamiliar with them. In 1893, the bellboy at the Hotel Brian mistook Data's uniform for pajamas. Later, while talking to the android, he expressed his wonder at the idea that a man could ride into town in his pajamas and win enough money to build a horseless carriage and make a million dollars. (TNG: "Time's Arrow")
In 2024, Vin expressed his admiration for Commander Sisko's uniform, also erroneously believing they were pajamas. (DS9: "Past Tense, Part I")
In 2152, Denobulan Doctor Phlox wore pajamas while hibernating in his quarters. (ENT: "Two Days and Two Nights")
The final draft script of "Two Days and Two Nights" identified these as "Denobulan pajamas."
When Nog sold his possessions in 2372 prior to leaving for Starfleet Academy, Rom purchased his pajamas for two strips of latinum. Later, an enraged Quark ripped the clothing from his hands. (DS9: "Little Green Men")
Captain Kathryn Janeway wore shoulder-free pajamas when talking to Telek R'Mor over com in her quarters. (VOY: "Eye of the Needle")
B'Elanna Torres wore dark red stretch-velvet pajamas during a period she was avoiding sleep to fix Automated Unit 3947. (VOY: "Prototype")
Tom Paris was interrupted in his quarters the night before undertaking the first flight to break warp 10, and was wearing a dark blue sleepwear robe with stitching details along the collar. (VOY: "Threshold")
In 2376, when Tom Paris was accused by Tuvok of altering one of the Vulcan's holoprograms by putting pajamas on the Oracle of K'Tal, he made a joke of it, suggesting, "Well, maybe he overslept." Paris was not responsible, however. (VOY: "Live Fast and Prosper")