Latin. Act of the mind. Intent. The animus enters into many questions of law, as an essential element. Thus, for example, in acquiring a domicile, mere residence is not -sufficient, if there be not the intention to acquire it, as domicile can only be acquired animo et facto. Again, consent, which is essential to all contracts, is an actus animi, and is presumed in all cases where the contract is ex facie regular. But this presumption may in certain cases be reargued, as in the reduction of a deed, on the ground of force or fear. In such cases, however, the burden of proving lies upon the person challenging the contract or deed.