Technically, in mathematics, a vector is just any object which obeys certain axioms. It need not have any meaning or content. In this sense, asking for the meaning of a vector v would be like asking for the meaning of the natural exponential base e (te'o): it really does not have one, it is just a number which happens to exist and have certain properties, it does not represent anything further.
However, in physics, computer science and applications, and linear algebra, it is often the case that vectors encode some sort of information. A vector may represent a displacement or a velocity or the state of a particle, or it could be used in order to represent a color or a list of inputs or genetic information (although some conceptualizations of these usages may not actually satisfy the vector axioms of math, so be careful with what you are imagining), or it might store the solution to a system of linear equations.
The question is: should Lojban by default force the user to assume a meaning or not? If meaning/content is assumed, then either the terbri for meaning must be deleted via zi'o or it wouldbbe filled with something like the word "nothig" in meaning (which is arguably logically abusive); in the context of abstract algebra, this would be annoying. It is also a mathematically unnecessary condition. On the other hand, having such a terbri would be really helpful in those other situations and could be used in order to understand why the vector is being used (since it has meaning, one can explain its meaning) and to distinguish between vector objects (velocity vectors do not live in the same space as displacement vectors, even if the vector spaces are isomorphic; separating them is useful).
