Key Takeaways

  • Patent ambiguity occurs when uncertainty appears directly on the face of a document, making its intent unclear.
  • Courts generally cannot use external evidence to clarify a patent ambiguity, unlike latent ambiguity.
  • Patent ambiguities commonly arise in contracts, wills, and construction agreements where wording is inconsistent or contradictory.
  • To avoid disputes, contracts should use clear, consistent terms, and parties should address ambiguities before signing.
  • Patent ambiguities can invalidate a legal document if intent cannot be reasonably interpreted from its text.

What Is Patent Ambiguity?

Patent ambiguity refers to uncertainty on the face of a legal document. This gives the agreement or contract an indefinite meaning. When a document includes a patent ambiguity, no external evidence can show the testator's intention, which remains unclear. A patent ambiguity may invalidate an agreement or contract.

Patent Ambiguity: What Is It?

Also known as intrinsic ambiguity, ambiguitas patens, or Section 93 of the Indian Evidence Act, patent ambiguity makes the intention behind a legal document unclear. Relying on the plain meaning of the words doesn't allow for clear interpretation. Instead, the document's obscure or senseless language makes its overall meaning ambiguous.

This happens, for instance, when a contract includes two sale prices that contradict each other. Patent ambiguities also arise in last wills and testaments, such as when a will doesn't state the gift for the beneficiary or offers the gift to many beneficiaries. Courts often find that a last will with a patent ambiguity is invalid. Most won't consider outside evidence to decide the meaning of the testator's intent.

Why Is Patent Ambiguity Important?

Patent ambiguities are different from latent ambiguities, or Section 95 of the Indian Evidence Act. The latter happens when a document's language is clear. However, external evidence or information means one could interpret it in at least two different ways.

A latent ambiguity also arises when the language in a document doesn't match a particular person or thing, but two or more persons or things match the description when combined. In this case, extrinsic evidence may clear up the ambiguity. If it doesn't, the contract may become invalid.

Latent ambiguities often arise in construction contracts, usually from:

  • general conditions
  • the principal agreement
  • change orders.

Normally, ambiguous language in a contract is interpreted against the party that created it. In the case of public construction contracts, it's the contractor's responsibility to name and resolve ambiguities before signing the contract. After signing, contractors can argue only latent ambiguities.

As PENNDOT vs. Mosites Construction Co. illustrates, the parties agreed the latter would be paid in pounds of steel. The contract didn't include the weight of washers, nuts, or bolts in its calculation. The contractor didn't realize this until after signing. The ambiguity wasn't clear on the face of the contract. Both the Board of Claims and the Commonwealth Court decided the ambiguity was latent and ruled in favor of the contractor.

Latent ambiguities can also affect contractors placing bids. When bidding for an FDA contract, a latent ambiguity prevented the RELI Group from competing intelligently for a contract. However, a latent ambiguity in a solicitation from Miracle Systems still resulted in a rejected proposal. Companies such as IAP, Singleton Enterprises, Deco Security Services, Input Solutions, Inc., Ashe Facility Services, Inc. Ashland Sales and Service Company, and The Arora Group, Inc. all alleged latent ambiguities against government agencies as well.

Latent ambiguities also arise in last wills and testaments. This especially happens when the wording may apply to a number of people or objects. For instance, a will may refer to a name that several family members share or to a name that combines multiple family members' names.

The case Horadam V. Stewart explores the ambiguity that happens when interpreting the phrase, "the royalties from all posthumous publication of any of my works" from a last will. To resolve the case, the court first decided if the wording was ambiguous. Then it decided the ambiguity was latent. The court then allowed various evidence to understand the testatrix's intent.

Patent Ambiguity in Contracts and Business Agreements

Patent ambiguity frequently arises in commercial and construction contracts, where vague or conflicting terms can lead to disputes about performance, payment, or scope of work. Courts distinguish between patent and latent ambiguities to determine whether extrinsic evidence may be introduced. When an ambiguity is apparent from the contract’s language itself, courts classify it as patent and typically refuse to admit outside evidence to interpret it.

For example, a construction contract that specifies “paint all exterior walls and ceilings” could create a patent ambiguity if the contract drawings or specifications never clarify whether covered porches count as “exterior ceilings.” Because the uncertainty appears directly in the text, the court would treat it as patent. Contractors are generally responsible for identifying and resolving such ambiguities before submitting bids or executing the contract.

Courts have repeatedly emphasized that patent ambiguities place the risk on the drafting or bidding party. In FAR 52.236-21, the “Specifications and Drawings for Construction” clause directs contractors to request clarification from the contracting officer before proceeding. Failure to do so can forfeit claims for additional compensation. This approach ensures that parties cannot later rely on self-serving interpretations when the ambiguity was obvious on the face of the agreement.

In commercial settings, such as lease or sale agreements, patent ambiguity may involve unclear pricing terms or contradictory provisions. For instance, if a contract states both “$10,000 per month” and “$120,000 annually,” a patent ambiguity exists because both terms cannot be simultaneously true. Courts will attempt to construe the contract using ordinary meaning and contextual reading, but if intent cannot be ascertained, the clause may be void for uncertainty.

Common Mistakes

  • Including either type of ambiguity in a legal document. When drafting a contract or agreement, use language that is as clear and concise as possible without leaving out important information. Doing this will make the document easier to understand and will remove multiple interpretations.
  • Assuming an ambiguity allows the court to rewrite the document in question. When considering evidence to resolve an ambiguity, courts don't allow legal representatives to rewrite or add words to a document. Instead, they may use evidence to interpret the testator's intention only.
  • Believing an attorney is liable for ambiguities. Courts have held attorneys liable for omitting clauses from legal documents. However, lawyers are not liable for drafting ambiguous documents.

Patent Ambiguity in Wills and Estate Documents

Patent ambiguity also arises frequently in last wills and testaments, where imprecise wording can obscure the testator’s true intent. Examples include provisions that fail to name a specific beneficiary or refer to multiple potential beneficiaries (“to my cousin Alex,” where more than one cousin shares that name).

Courts apply strict standards when interpreting wills containing patent ambiguities because the ambiguity appears within the document’s language itself. For instance, in In re Estate of Barker, a Florida probate court noted that patent ambiguities cannot be resolved by introducing extrinsic evidence, such as oral statements made by the deceased. The will must “speak for itself,” and where meaning cannot be determined, the ambiguous clause may be declared void.

In contrast, if the will’s language seems clear but external facts make it uncertain which person or property was intended, the ambiguity is latent, and courts may consider outside evidence to clarify intent. This distinction is crucial in estate planning, where a single unclear phrase can alter the distribution of assets.

To prevent patent ambiguities in estate documents:

  • Use precise names and unambiguous descriptions for beneficiaries.
  • Avoid conflicting terms (e.g., two different bequests for the same asset).
  • Review all clauses for consistency with related provisions.
  • Work with a qualified attorney to ensure drafting clarity and compliance with state probate law.

By maintaining linguistic precision, testators and their counsel reduce the risk that a court will find the will ambiguous or partially invalid.

How Courts Resolve Patent Ambiguity

When courts confront patent ambiguity, they first determine whether the ambiguity is resolvable from the document itself. The primary goal is to give effect to the drafter’s or parties’ intent without rewriting the contract or will. Courts typically follow these steps:

  1. Plain Meaning Rule: They interpret words according to their ordinary meaning.
  2. Contextual Reading: They examine the entire document to harmonize conflicting terms.
  3. Contra Proferentem Doctrine: If ambiguity persists, courts construe the language against the drafter, especially in contracts.
  4. Invalidation: If intent cannot be determined, the ambiguous provision may be struck down as void or unenforceable.

However, courts will not add missing terms or rewrite contracts. As emphasized by the Florida Business Litigation Blog, “ambiguity does not authorize courts to redraft a bargain” — the role of the judiciary is interpretation, not revision.

Frequently Asked Questions

  1. What is the main difference between patent and latent ambiguity?
    Patent ambiguity is apparent from the document’s text itself, while latent ambiguity becomes evident only when applied to external facts.
  2. Can courts use external evidence to interpret a patent ambiguity?
    Generally, no. Courts refuse to consider external or parol evidence when the ambiguity is patent, since the document’s wording is already unclear.
  3. How can I prevent patent ambiguity in a contract?
    Use precise, consistent language; define key terms; and review the document for internal contradictions before signing.
  4. What happens if a will contains a patent ambiguity?
    If a will’s wording is unclear and the intent cannot be inferred from its text, the court may declare the ambiguous provision void.
  5. Should I hire an attorney for ambiguous contract or will drafting?
    Yes. Consulting an experienced attorney can prevent costly disputes and ensure your documents are enforceable. You can find a qualified attorney through UpCounsel for guidance on drafting or resolving ambiguous terms.

If you need help with patent ambiguity, you can post your legal need on UpCounsel's marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb.