According to the Black’s Law Dictionary, Ad idem means to the same point, or effect. It makes or goes to establish the same point ad idem facit.
Ad idem is a legal term that means "in agreement" or "at a meeting of the minds." When two parties to a contract have the same understanding of the contract's terms and conditions, the parties are said to be "ad idem" on the terms and conditions. A valid contract requires such meeting of minds.
Mayawanti v. Kaushalya Devi
In the year 1973, the appellant herein filed a civil suit against the respondent herein, seeking a decree for specific performance of the contract, or, in the alternative, a decree for a total sum of Rs. 16,000, including the earnest money of Rs.5,000, based on averments that she had entered into an agreement dated 16.9.71 with the Respondent for the purchase of a property with two Kohlus of 20 H.P. electric Motor, etc., installed therein and that, if Smt. Lajwanti did not join in the execution of the sale deed, the Respondent would sell her half share of the property for half the sale price; that pursuant to this agreement the Respondent handed over to the Plaintiff-appellant possession of her share of the property but later as arbitration proceedings were going on between the Respondent and her co-sharer Smt. Lajwanti, the Respondent took back the said agreement (styled as receipt) and thereafter illegally took possession of the property from the appellant and declined to execute the sale deed in terms of the agreement.
According to this instance, if a contract is to be made, the offeree's intention to accept the offer must be conveyed without leaving any doubt as to the reality of acceptance or the coincidence of the terms of acceptance with those of the offer. The general rule is that acceptance must be absolute and in accordance with the terms of the offer. There cannot be a contract for specific performance if the two minds were not ad idem in regard to the property to be sold. The court cannot order specific performance if the parties were not ad idem on the contract's subject matter. If the plaintiff understood the terms to have included the building but the defendant understood it to have excluded the building and the so called memorandum Ext. PW- 11/A did not mention the building, there is no contract before the court for specific performance.
For the reasons stated above, we agree with the High Court's decision that the parties did not have a valid and enforceable contract as evidenced by Ext. PW-11/A. As a result, this appeal is dismissed, albeit with no order as to costs because to the peculiar facts and circumstances of the case.
USAGE OF THE TERM AD IDEM:
In this case the two parties of a contract with different understanding about the subject-matter of a contract had made a contract between themselves. Here, the plaintiff thought that the subject matter was property (i.e. building), but the defendant thought that the subject matter was machinery in that property. Since, the parties of the contract do not have the same idea about the subject-matter of the contract and since there was no meeting of minds, the court stating the minds of the parties were not ad idem, declared that the contract is not valid.