Agreements void for uncertainty: indeterminate essential terms invalidate contracts unless capable of being made certain. Agreements whose meaning is not certain or capable of being made certain are void. Uncertainty is cured where the description is a known article of commerce, where the parties' trade indicates the meaning, where the subject matter is clearly identified, or where an essential term like price can be fixed by an agreed mechanism or third party. By contrast, terms leaving an essential choice unresolved without a method of ascertainment render the agreement void.