Let $\Omega \subseteq \mathbb R^n$ be a nice open, connected, bounded subset (say with Lipschitz boundary) and let $f:\Omega \to \mathbb{R}^n$ be a Lipschitz map.
Is there a standard terminology for the following property?
$|f^{-1}(y)| \le 1$ for almost every $y \in \mathbb R^n$, where $|f^{-1}(y)|=1$ refers to the cardinality of the preimage.
I guess that reasonable suggestions could be "injective a.e. in the image" or "almost injective" or something like that. However, I wonder whether there is an accepted terminology I could use, and I don't want to "overload" or get into conflict with other terminologies. (I can guess that "almost injective" could be referring to a map which is injective after you exclude a set of measure zero from your domain).
(The mathematical context is the Area/Coarea formula.)
At least in the context of elasticity theory, this is known as "injectivity almost everywhere", see, e.g., Ciarlet's "Mathematical Elasticity vol. 1", Problem 5.7 (following the work of Ball) and Section 7.9 (following Ciarlet-Nečas).