Pyjamas were clothes that were worn in bed.
When Charlotte Pollard described Chief Stewart Weeks' nose as being "redder than Mr Lenin's pyjamas" on 4 October 1930, the Eighth Doctor disputed they were red; he claimed that they were a "sort of mauve" when the Doctor took a train with Lenin from Switzerland to Petrograd. (AUDIO: Storm Warning)
After his recent regeneration, the Tenth Doctor fought the Sycorax leader in the pyjamas he was given to wear by Jackie Tyler, which belonged to an acquaintance of hers. He commented on finding fruit in the dressing gown. (TV: The Christmas Invasion)
Adric's attire was sometimes derisively compared to pyjamas. In December 1981, Robert DeValley referred to him as "pyjama game". (AUDIO: Iterations of I) During an argument, Tegan Jovanka once called him "Pyjama Boy". (AUDIO: The Contingency Club)