In order to describe cube state we need to introduce orientation concept of pieces.
Edge is in correct orientation if we can find sequence of moves that allows to insert one in correct place but not using two defined faces which are opposed to each other. Choice of opposed faces is unrestricted but remember that you can’t change you choice later. It only depends on cuber’s preferences.
Picture below shows examples of various edges orientations using R and L as defined opposed faces. Blue-red piece is in correct orientation because it’s in correct place. White-red piece is in incorrect place but using F move we can put it to target so it is also in correct orientation.
The other situation is when we look at blue-white edge. In order to put it in correct place we need to make move R and U. But we defined orientation by faces R and L so this piece is in incorrect orientation.
Corner is in correct orientation for defined opposed faces if any of defined color of mentioned faces is on any of defined faces. So when we defined two faces as U and D for example from picture displayed below we can see that blue-red-white corner is in correct orientation because is in correct place. Corner green-red-yellow is in incorrect place but color of face D is on U so it is also in correct orientation. Corner blue-white-orange is in incorrect orientation because color from face D or U is on side face.