Solubility product is defined as
product of molar concentration of ions of a salt as per stoichiometry in a saturated solution
product of molar concentration of ions of a salt as per stoichiometry in a saturated solution at STP
product of molar concentration of ions of a salt as per stoichiometry in a supersaturated solution
product of molar concentration of ions of a salt as per stoichiometry in an unsaturated solution
Solubility product is product of molar concentration of ions of a salt as per stoichiometry in a saturated solution.