A plaid flannelshirt shirt worn untucked and unbuttoned, typically with an undershirt. On hot days it's taken off and tied around the waist by the arm sleeves.
The Burnaby Dinner Jacket is the choice of wear of Canadian lumberjacks.
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.