"What's the plural of abacus?"

Which is correct: Abacuses or Abaci?

The word abacus comes from the Greek word "abax," which means "board" or "slab." Being of Greek origin, the Greek pluralization of the word “abacus” is “abaci”.  This follows the same rules as many similar words ending in -us such as cactus, radius and platypus.

However, over time, the word has evolved, and the anglicized plural form "abacuses" has slowly grown in usage.

See the graph at the bottom of the page for a comparison of the instances of each word in written English over time.

Is Abacus a Countable or Uncountable Noun?

Abacus is a countable noun, which means it refers to a specific object that can be counted.

In English grammar, nouns can be categorized as either countable or uncountable. Countable nouns are things that can be counted, such as "book," "apple," or "chair," while uncountable nouns are things that cannot be counted, such as "water," "sugar," or "furniture."

For example, if you have two abacuses, you can say, "I have two abacuses," because "abacus" is a countable noun. In contrast, you cannot say, "I have two sugars," as "sugar" is an uncountable noun. Instead, you can say, "I have two packets of sugar," or "I have two spoonfuls of sugar."

Conclusion

In conclusion, the plural of abacus can be either "abaci" or "abacuses," and both are grammatically correct. The choice between the two forms depends on the context and personal preference.

Regardless of the plural form used, the abacus remains an important tool for teaching and learning mathematics, as well as for providing a fascinating insight into the history of human innovation.