What is the TRUE difference between TrueType outlines and PostScript outlines?


I've done some Internet searches, but all I've got is some big words such as "quadratic B-splines" or "cubic Bezier splines". I've examined some fonts and I've been assuming that TrueType outlines are controlled by on and off-curved nodes (which are easier to adjust), and PostScript outlines by on-curved and handled nodes (which feel much more like "Bezier" to me). But I've just found out that most fonts I have with the OTF extension are recognized with "OpenType Layout, TrueType outlines" and with "(OpenType)" going after their family names (they've got PostScript outlines as I assumed).