sigma

sigma — noun

1. The 18th character in the Greek writing system, written as Σ (uppercase) or σ an

1.名詞B1
釋義

The 18th character in the Greek writing system, written as Σ (uppercase) or σ and ς (two lowercase forms).

例句

Mauricio learned to write the letter sigma in his Ancient Greek class.

letter name in language-learning context

In maths, the capital sigma (Σ) means you should add up all the terms.

capital Σ for summation in mathematics

文法句型

sigma + [verb]

the letter sigma

用法筆記

Sigma has two lowercase forms depending on position in a word: σ (medial, used everywhere except the end) and ς (final, used only at the end of a word). This distinction matters when writing Greek text. Outside of Greek-language contexts, sigma is most often seen in mathematical notation (Σ for summation) and statistics (σ for standard deviation).

常見錯誤

❌I wrote ς in the middle of the Greek word.
✅I wrote σ in the middle of the Greek word.
💡The form ς (final sigma) is only used at the end of a word; σ is used in all other positions.