An interpreter's terminology, as opposed to that of translators and terminologists, is meant for the moment only; terms that are noted come from a certain situation and have been used by a certain group of people. What counts is that a term helps communication run smoothly and that everybody knows what the speaker is referring to. An interpreter's terminology may include improvised terms that would certainly not be understood outside the particular situation or group of people; there may even be “false" terms that would never make their way into a dictionary, such as when people talk about frogs even though the actual animals being discussed are toads. They may also include more general target language terms being used to translate a rather specific source language term. While Germans could easily talk about a Handgabelhubwagen (hand forklift truck) all day, Spanish-speaking people might tend to keep it a bit more general and say carretilla, confident that everybody knows what is meant anyway. Translators and terminologists are far less free to generalize (and interpreters, in a way, are meant to generalize if the situation calls for it), as the recipient will not necessarily share the situational knowledge like participants in interpreted communication do. So all in all, interpreters' work is more situation-oriented, which is why, ideally, their terminology includes quite a number of situation-related information, referring to a certain conference, customer, speaker or particular circumstances.
Generally speaking, interpreters' terminology databases tend to be far less sophisticated than what “proper" terminology systems have to offer. . .