1. the closeness of an experimental result to the true or accept value
2. a chemical or substance in sample which is studied
3. a solution containing only reagent without the interested substance or chemical, typically used to zero an analytical instrument and ensure that any reagent used do not contribute to overall measurements
4. the amount of a substance present in a given mass or volume of another substance
5. a plot of how the instrumental response, called analytical signal, changes with the concentration of the substance to be measured