The planets were roughly divided in ancient times (and nowadays by the IAU, the International Astronomical Union) into two types: the Fixed stars and the Moving stars.
The Fixed Stars are called in plural Koch•vey She•vet. The singular is today’s word: Ko•chav She•vet. The word ‘she•vet’ means ‘sitting’ or ‘being settled.’ In Biblical Hebrew, ‘she•vet’ is considered an Infinitive Absolute − the very basic, nucleus form of a word or concept. It is, hence, the core word for ‘stationary.’ Of course, our current understanding is that nothing is really fixed in outer space, but because of the great distance of these stars from Earth (A•retz), they look as though they were stationary (She•vet).
The Moving Stars category includes our seven Solar System planets. They are called in Hebrew (in plural form) Koch•vey Le•chet. The singular is Ko•chav Le•chet. The word ‘le•chet’ means ‘going’ or ‘walking.’ In Biblical Hebrew, ‘le•chet’ is considered an Infinitive Absolute − the very basic, nucleus form of a word or concept. It is, hence, the core word for ‘moving.’ In fact, the mere English name ‘planet’ comes from the Greek name πλανήτης (planetes) which means ‘moving about’ (something like ‘moving back and forth’).
The IAU, indeed, changes its definitions from time to time as the science of Astronomy develops, but we still count seven planets in our Solar System and still call them ‘moving stars,’ both in Hebrew and English since from the Biblical era to today.
Some of the planets, perhaps, were not known during the biblical era and do not have Hebrew names (Uranus and Neptune).