These two words, however, should NOT be used interchangeably. They are two very different words, with different meanings, and indicate two different places in the process towards marriage. In fact, with regards to “dating” I should not be too quick to say that this term necessarily included in the process towards marriage.
There is a fundamental different between courtship and dating. Dating does not necessarily mean the persons are interested in marriage at all, let alone interested in determining if this person they are dating might be the person they should marry one day. For many, dating is a form of entertainment, something to do with one’s free time. It is completely possible to date someone with absolutely no intention of considering them for marriage.
Courtship, on the other hand, absolutely does have marriage in mind. To say that you are courting someone or are in a courtship is basically to say “I am moving toward potential marriage with this person, and we shall see how it goes.” It also absolutely implies exclusivity with the person. To enter into courtship means to put a hold on considering any other person for marriage in order to focus on determining if this person you are courting is the one to become engaged to marry.
Notice that courtship is not engagement. To become engaged to a person is to make a decision to marry. Courtship wants to focus only on the person you “think” might be the one you want to spend the rest of your life with.
Those who enter into courtship are pretty sure they have found the one. They are not going into courtship with any thought that it is not the one. Otherwise, they would not be exclusive. It is quite a big step to become formally exclusive with someone. It is a practice run of making the formal decision to forsake all others on the day you exchange vows. In courtship, you do forsake all others, but not as a vow, but rather as a trial run.
Because it means exclusivity, courtship needs to be a short period of time, and have a definitive end. It cannot be open ended. Otherwise, you risk hurting each other in a way you do not wish to, but can simply because you are not yet married. It risks looking like and acting like you are married, when you have not formally made the commitment. It risks giving in to the temptation to do that one thing reserved ONLY to married couples because you become so used to each other and, what the heck, you love each other and are practically married anyway, so why not?