Definition

1. Adjective:

   • Having three sides: Describes a geometric figure or shape that possesses exactly three sides.
   • Involving three parties or groups: Describes an agreement, negotiation, or relationship that includes three distinct participants.

2. Noun:

   • A three-sided polygon: A flat, closed geometric figure with three straight sides and three angles; a triangle.

Usage Examples

• Adjective:

  • The trilateral design of the courtyard created a unique sense of space. (The three-sided design of the courtyard created a unique sense of space.)
  • The leaders engaged in trilateral discussions to address the regional crisis. (The leaders engaged in three-party discussions to address the regional crisis.)

• Noun:

  • A square can be divided into two congruent trilaterals. (A square can be divided into two congruent three-sided polygons.)

Advanced Usage

• In diplomacy and trade: The term is frequently used in political and economic contexts to describe formal cooperation between three nations or entities.
  • The new trilateral trade agreement aims to reduce tariffs between the countries.
• In geometry: While synonymous with "triangle," "trilateral" is a more formal term emphasizing the property of having three sides.

Variants and Related Words

• Triangle (n): The more common term for a three-sided polygon.
• Tripartite (adj): Involving three parties or divided into three parts. Often used interchangeably with "trilateral" in non-geometric contexts (e.g., a tripartite agreement).
• Trilaterally (adv): In a trilateral manner.
  • The issue was resolved trilaterally.

Synonyms

• Adjective (geometric): Triangular, three-sided.
• Adjective (multilateral): Tripartite, three-party.
• Noun: Triangle.

Antonyms

• Adjective: Bilateral (two-sided), multilateral (many-sided, typically more than three).
• Noun: Polygon (general term for multi-sided figures, not specifically three).

Related Phrases/Idioms

• Trilateral commission: A specific, proper noun referring to a non-governmental discussion group founded to foster cooperation among North America, Europe, and Asia-Pacific.
  • He was invited to speak at a meeting of the Trilateral Commission.

Adjective

1. having three sides
   • a trilateral figure
2. involving three parties
   • trilateral talks

Noun

1. a three-sided polygon