A kilt was a knee-length skirt-type garment which was the traditional dress of men and boys in the Scottish Highlands.
Jamie McCrimmon spent his time travelling with the Second Doctor wearing his kilt, even when it was too cold to do so. (TV: The Highlanders, TV: The Abominable Snowmen et all)
When the Fifth Doctor was giving Erimem a tour of the TARDIS, he told her the kilt in the wardrobe belonged to Jamie. (AUDIO: No Place Like Home)
Burrows compared Captain Kybo's uniform to a kilt. (AUDIO: Judoon in Chains)