A canopy bed is a decorative bed somewhat just like a 4-poster bed. A typical cover bed often features posts at each of the 4 corners extending 4 toes high or extra above the mattress. Ornate or ornamental material is usually draped throughout the upper area between the posts and a strong swath of fabric could create a ceiling, or cover straight over the bed.
A 4-poster bed is a bed with 4 vertical columns, one in each nook, that support a tester, or upper (often rectangular) panel. This tester or panel will often have rails to allow curtains to be pulled around the bed. There are a number of vintage 4-poster beds extant dating to the 16th century and earlier; many of those early beds are highly ornate and are produced from oak. An example of such an early 16th-century 4-poster resides in Crathes Castle, which was made for the unique fortress house owners in the Burnett of Leys family.