No dearie, that's the very same thing-the only difference is the amount of it. You grind to gain access to content-in an MMO, grinding becomes farming because you are buying content for sale from other players who don't understand the core concept of 'fair trade'.

Is it unreasonable to say that you grind for new equipment and new spells when they become available? If so, could it not be argued that you are farming gil, which you then use to 'unlock' content that is in the game?

Let's get something straight. If there IS a legitimate distinction between farming and grinding, it's a very slippery slope and one that were I you I would not go galabanting around stating there's a difference when that difference is in the minutae of fine print and marginally different wordings.