Yes, best to call this (Jamie’s) a belted plaid (essentially a wearable blanket). They are sometimes called Great Kilts, which can be confusing. Modern kilts are tailored and ready to wear. Plaids are only large pieces of fabric.
The one Jaimie is wearing is called the ‘Great kilt’ and is usually 8 yards of material. This was really the way you had to put them on, and they were very serious about those pleats. The more modern kilts are around 5 or 6 yards, depending,and they make them for different seasons and purposes (utility/cargo etc) too now.