Models vs. Structures

Why are both the terms 'structure' and 'model' used in mathematical logic / model theory? Are they just holdovers from different subjects or is there a principled reason for having both?

For clarification, I'm not confused about any actual definitions or usages, just why both terms came to be used; I could, after all, survive perfectly well using exclusively one or the other with little chance of confusion.

Solution 1:

Models are structures, and structures are models. But when we say "model" we mean that there is a particular theory which holds in the structure, and when we say "structure" we are mainly interested in an arbitrary interpretation of the language.

Solution 2:

A structure is a set with some interpretable symbols(constants, relations and functions) within a fixed language. You do not ask for more from a structure.

However...

A model (of a theory) is a structure which satisfies the axioms of the theory. It makes more "structural sense"...

Maybe an example brings more clarification: Consider the theory of groups. $\mathbb Z$ is a structure in $\mathcal{L}=\{e, \cdot, ^{-1}\}$ but not a model since it is not a group. On the other hand, $\mathbb R- \{0\}$ is an $\mathcal{L}$-structure and further a model as it is indeed a group.

This is what I more or less know within a model-theoretic view. Someone else may give an answer also considering a perspective of universal algebra.