Multiword expression

For a shorter definition, MWEs can be described as "idiosyncratic interpretations that cross word boundaries (or spaces)".

Example #3 in French: la moutarde monte au nez.

Let us add that a tense variation is allowed for the verb but we cannot determine what is the part of speech for the whole expression because it is a sentence.

According to Sag et al. (2002), multiword expressions are, apart from disambiguation, one of the two key problems for natural language processing (NLP) and especially for machine translation (MT).

For example, the German MWE ins Auge fassen can only be translated by the English one-word term envisage.

Nevertheless, an example based MT system has to apply different rules for the translation of continuous and discontinuous MWEs as it is harder to identify a discontinuous MWE in a sentence where words are inserted between the different components of one MWE.