Not everything which comes from the sky is good for us. But if we’re worried about comets or meteorites crashing into Earth, we should also remember that much of what comes to us from the sky can be the source of momentous discoveries.

The article discusses the use of metaphors in the terminology of astronomy and astrophysics. The terminology of these fields is relatively stable, characterized by terminological diversity, thus allowing to draw sufficiently general conclusions. Three cases are to be considered: (a) first, the metaphor as a powerful source of terms, assuming the denominative function, (b) the terminological metaphor which leaves a certain domain and which penetrates into the general language, which is sometimes called determinologization, and, (c) finally, the terminological metaphor migrating from one specialized domain to other terminologies in which it is newly used to denote another concept, this phenomenon sometimes being referred to as transterminologization. The three processes are analysed and documented, using French and Czech examples, excerpted from specialised texts (encyclopaedic dictionary and newspaper articles).