Let $M$ be a finitely generated graded module over a graded ring $R$. Let $\mathcal{F}$ be the corresponding coherent sheaf on $\operatorname{Proj} R$. There is a natural map of graded $R$-modules
$$\phi \colon M \to \Gamma^\*(\mathcal{F}) := \bigoplus\_{n} \Gamma(\operatorname{Proj} R, \mathcal{F}(n)).$$
If I recall Ravi Vakil's notes correctly, $M$ is called *saturated* if $\phi$ is an isomorphism.



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> Is there a term (perhaps semi-saturated, or some such) for modules $M$ such that $\phi$ is injective?
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This concept is appealing for several reasons. For one thing, it is easier to test "semi-saturatedness" than saturatedness; e.g., unless I am mistaken, $\phi$ is automatically injective if $M$ admits any positive-degree homogeneous nonzerodivisor. For another, at least if $R$ is a polynomial ring, $M = R/I$ is "semi-saturated" iff $I$ is a saturated ideal of $R$. (Note that the definition of "saturated ideal" is different from the definition given above for "saturated module", and I do not think the two are equivalent for ideals.)



A name for "not quite saturated" graded modules
To elaborate on Karl's comment:


Let $m$ be the irrelevant ideal of $R$, then there is a short exact sequence:


$$0 \to H\_m^0(M) \to M \to \Gamma^\*(\mathcal{F}) \to H\_m^1(M) \to 0$$


(see Eisenbud's book, Theorem A4.1, p. 693). Here $H\_m^i(M)$ denote the local cohomology modules. So the map is injective precisely when $H\_m^0(M):= \cup\_n (0:\_M m^n) = 0$. I believe such module is called $m$-*torsion-free* (don't know a reference off hand, may be Brodmann-Sharp's book on local cohomology?). 


Also, it is equivalent to $m$ contains a non-zerodivisor on $M$ (may be that's what you meant in the last paragraph?)


