Abstract
While I was working on the Dictionary of Navigation I realized that I had to adopt different patterns for the acceptance of phraseological units. I started selecting not only the simple derivative forms (nouns, adjectives, adverbs, verbs) but also idioms, phraseological units or preferential combinations. The «preferential combination» concept has been adopted in an ample sense, as an structure formed, minimum, of two words with fixed contents, that is to say, with fixed semantics.