Winter sowing is planting outside in miniature green houses. Usually recycled containers like glass jars, milk jugs etc are used.
https://extension.psu.edu/succ.... The concept is similar to the use of cold frames which we old timers used.
Fall planting usually refers to planting for a second season. Usually for plants that are somewhat cold tolerant like brassicas, spinach, carrots Which produce before hard freezes or in a few cases overwinter.