The technical difference
A pallet has a top deck and a bottom deck, joined by stringers or blocks. A skid has a top deck only: it sits directly on its runners, with no boards underneath. The skid is the older design, and the bottom deck was added later to make the platform more stable and easier to stack.
How the words are used in Canada
In everyday use across Canada, and especially in shipping and warehousing, people say skid and pallet for the same thing. A carrier quoting a rate per skid and a supplier selling you pallets are almost always talking about the same standard 48 x 40 platform with a top and bottom deck.
So if someone asks you for six skids of product, they nearly always mean six pallets. The distinction only matters when you are ordering the platforms themselves.
When the difference matters
The bottom deck spreads the load. That makes a true pallet the better choice for stacking loaded pallets on top of each other and for most warehouse racking, where the bottom boards bridge the rack beams.
A true skid uses less wood, so it costs less and weighs less, and empty skids nest more tightly. Skids suit heavy machinery and equipment that sits in one place, or loads that will be dragged rather than lifted. They are a poor choice for racking and for stacking loaded units.
How to order the right thing
Describe what you need rather than relying on the word. Give the size, say whether you need boards on the bottom, and mention whether the load will be racked, stacked, or shipped overseas. Magic Pallets supplies standard and custom pallets and can build to your description, whichever name you use for it.