Ambiguity, doubtfulness, double-meaning, obscurity. There are two species of ambiguity--'latent' and 'patent.' Where the words of a document as they stand are quite clear and intelligible but it turns out that they can apply equally well to two or more persons, or to two or more things, that is a 'latent ambiguity,' and parol evidence is admissible to shew which was really meant. This is not contradicting the document, because each answers the written words equally well. A 'patent ambiguity,' on the other hand, is one which appears on the face of the document and renders it unintelligible, e.g., a legacy of 100l. to ___. No parol evidence is admissible to supply the missing name; but see Watcham v. A.G. of East Africa, 1919 AC 533 (Powell on Evidence). The rule is expressed accordingly in the two following Latin maxims:
Ambiguitas verborum latens verificatione suppletur; nam quod ex facto oritur ambiguum verificatione facti tollitur. Bacon.--(a hidden ambiguity of the words may be supplied by evidence; for whatever ambiguity arises from an extrinsic fact may be removed by extrinsic evidence.)
Ambiguitas verborum patens nulla verificatione excluditur. Lofft, 249.--(A patent ambiguity cannot be cleared up by extrinsic evidence.)