Hence these are called 'soilless' media. Horticultural researchers that work with soils or media are purists when it comes to such terminology. Some no longer even like the term 'media' and now prefer 'substrate'.
Growers are understandably less strict when using media or soil terminology.
Actually, for good reasons which you will read below, 'greenhouse soil' is a term that should be avoided, since most greenhouse crops are no longer grown in soil. However 'greenhouse soil' might be used in rare cases when a mix contained a significant proportion of mineral soil. Mineral soils and soilless media should be tested by different procedures. Any mix submitted with this yellow form will be tested as mineral soil . Apparently there used to be an option on this form for soilless mixes, but no longer.