# proprietary

/pɹəˈpɹaɪəˌtɛɹi/ (US) · /pɹəpɹˈaɪətəɹi/ (UK)

Source: https://englishreference.com/word/proprietary
Updated: 2026-06-20

## Senses

### 1. owned and protected

adjective · CEFR C1 · Technical · Academic

describing something that is owned by a company and cannot be used or copied by others without permission.

For teachers: relating to an owner or ownership; specifically, manufactured and sold only by the owner of the intellectual property rights.

- The company uses proprietary software that no other business is allowed to buy.
- The pharmaceutical giant maintains proprietary rights over the formula, preventing generic manufacturers from producing a cheaper version for the next decade.

Usage: Often used before nouns like 'software', 'technology', or 'information'.

### 2. behaving like an owner

adjective · CEFR C2 · Literary

behaving as if you own something or someone, often in a way that shows you are protective or jealous.

For teachers: expressing or manifesting a sense of ownership or exclusive rights, often used to describe a person's protective attitude or physical stance.

- He put a proprietary arm around his daughter as the strangers approached.
- She watched the restoration of the old house with a proprietary interest, despite having sold the property several months earlier.

### 3. an owner

noun · CEFR C2 · Formal · Archaic

a person who owns a business or a piece of land.

For teachers: an individual or entity that holds legal title to a property or business.

- The proprietary of the estate decided to open the gardens to the public.
- The original charter granted the proprietary full authority over the colonial territory, including the right to collect taxes and appoint local officials.

Teaching tip: In modern English, the noun 'proprietor' is much more common than using 'proprietary' as a noun.

## Examples

- The company uses proprietary software that only their employees can access.
- The manufacturer uses a proprietary charging port, meaning you cannot use standard cables from other brands.
- While open-source alternatives exist, many corporations prefer proprietary systems for the dedicated support and integrated security features that a single vendor can guarantee.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.