You should look at it like this: by using the article you signal that there will follow a complete list or a description of what you mean. Example:
a) Sometimes the author uses terms...
b) Sometimes the author uses the terms...
Given that the terms in question have not been defined previously to saying this, at this point in the utterance a person speaking English knows that:
a) in this sentence there will be a broad definition at best, the topic are not specific terms. I would expect the sentence to continue like "... nobody can easily understand". While that would be a description of a property of the terms, it is not a property which defines them in such a way that you could tell which terms exactly are being referred to.
b) in this sentence there will be either a list of terms (as in your example, where you list the exact three terms you mean) or some kind of definition which will at least make it possible to find out the exact terms, like if the sentence went on "... which Dr. Shmolinski defined as especially insulting in his seminal work How to Irritate People".
So the answer to your question "Should I have used "the" before "terms" in my post because i pointed them out later?" is "Yes, definitely". And note that you are talking about the words, not the actual suit, plaintiff and defendant they might refer to in that specific case. Their meanings or references are entirely irrelevant here.
By the way, the pronoun "I" is always capitalized.