This is a direct question many users have when searching. The short answer is: When referring to a "movable wheeled device," the two are synonymous in the vast majority of cases and are interchangeable. However, delving deeper into language habits, technical context, and industry preferences reveals some interesting nuances. This chapter will thoroughly clarify the relationship between these two terms for you.

Unified Etymology: A Common Starting Point

"Caster" and "Castor" both originate from the same Anglo-Norman word, whose root is related to the verb "cast" (to throw, to sprinkle). This vividly depicts two actions of a caster: first, the "rolling" of the wheel itself, and second, the flexible change of direction when a swivel caster "turns." Therefore, historically, using either word to refer to a caster was reasonable.

Principle of Generality: Interchangeable in Most Contexts

In non-specialized daily communication, general dictionary definitions, and even many general product descriptions, "caster" and "castor" are seen as spelling variants used to denote the same thing. When you see "chair castors" or "furniture casters," they almost certainly refer to the small wheels under chairs and furniture.

Subtle Differences and Usage Tendencies

Although interchangeable, in modern English, especially in professional and technical fields, some gradually formed usage tendencies exist:

1. "Caster" is More Preferred in Industrial and Technical Fields:

   • Global major industry market reports, mechanical engineering textbooks, and product standard catalogs more commonly use "Caster."

   • The company and brand names of internationally renowned caster manufacturers, such as "Colson Caster" and "Caster Central," mostly adopt this spelling.

   • When explicitly referring to the specific mechanical component category of "industrial caster," "Industrial Caster" is a more professional and precise expression.

2. Polysemy and Regionality of "Castor":

   • "Castor" is a polysemous word. Besides referring to casters, it also specifically means:

     • Castor Oil: A well-known vegetable oil.

     • Castor Sugar: A fine white sugar.

   • In British English, "castor" might be used slightly more frequently to refer to casters than in American English, but this difference is diminishing.

Authoritative Reference Opinion

Fowler's Dictionary of Modern English Usage notes: While using "castor" is never wrong, for the small rollers on furniture, it recommends using "castor"; for sugar, it recommends using "caster." However, in the industrial field, actual industry practice has tended towards "Caster."

Our Position and Recommendation

As a professional caster manufacturer based in China and serving the global market, we explicitly adopt "Caster" as our standard spelling in international business and technical exchanges. This is not only following the common practice of the global industry but also a reflection of our professional identity and precise positioning. What we produce are not vague general-purpose items but "Industrial Casters" and "Specialized Casters" precisely designed for specific application scenarios (medical, industrial, logistics, airport).

Beyond Spelling: Defining True Value Equivalence

For our customers, what matters more than spelling is whether the "Caster" we provide is truly "the same" as your expectations for high quality and reliability. Our commitment to equivalence lies in:

• Quality Equivalence Commitment: Regardless of where the product is sold, it adheres to the same stringent quality management system (ISO 9001) and production standards.

• Performance Equivalence Commitment: Every caster undergoes rigorous testing to ensure its load capacity, rust resistance, quietness, and other performance parameters are completely consistent with the specifications.

• Value Equivalence Commitment: Through our direct-from-manufacturer model, we eliminate middlemen, ensuring you obtain high-end quality products and professional technical support at a reasonable price.

Therefore, when you choose us, whether you call it a "Caster" or a "Castor," what you receive is equally excellent engineering quality, scenario-based solutions, and trustworthy long-term cooperation. We not only answer linguistic questions but also define quality standards in the caster field with concrete actions.