A trouser suit was a suit of clothing which included trousers. Whilst watching the Christmas speech by Queen Elizabeth II on television, Donna Noble suggested that the Queen should present the speech in a trouser suit. (TV: The End of Time)
In September 2005, journalist Cathy Salt wore a brown trouser suit. (TV: Boom Town)
Donna herself wore a black, striped trouser suit whilst investigating Adipose Industries. Meanwhile, Penny Carter wore a grey trouser suit. Both of them did it during the March of the Adipose. (TV: Partners in Crime)
Nyssa wore a trouser suit of plum purple velvet during her encounter on Monarch's ship, (TV: Four to Doomsday) her first encounter with the Mara, (TV: Kinda) her first encounter with Terileptils, (TV: The Visitation) during a trip to 1925, (TV: Black Orchid) during the fight to foil Neomorph Cybermen from their 2526 invasion of Earth, (TV; Earthshock) during a trip to Heathrow Airport during 1982 and 140,000,000 BC, (TV: Time Flight) and her first encounter with Omega during the Second Omega Crisis. (TV: Arc of Infinity)
Peri Brown wore a burgundy trouser suit during the Necros Incident. (TV: Revelation of the Daleks)
During her time as CEO of A Charitable Earth, Ace wore pinstripe trouser suits done in black and white. (AUDIO: Quantum of Axos; TV: The Power of the Doctor)