What is the meaning of " an order of magnitude less " ?

I need the exact meaning of this part in the passage :"The solubilities of niobium carbide and niobiumnitride in ferrite suggest that the solubilities

I need the exact meaning of this part in the passage :
"The solubilities of niobium carbide and niobium
nitride in ferrite suggest that the solubilities of these
compounds are about an order of magnitude less in
ferrite than the corresponding solubilities in austenite
at the same temperature."

or:I need the exact meaning of this part in the passage :\"The solubilities of niobium carbide and niobiumnitride in ferrite suggest that the solubilities of thesecompounds are about an order of magnitude less inferrite than the corresponding solubilities in austeniteat the same temperature.\"

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