级数 (jí shǔ) — (mathematics) series

Definition

noun
(mathematics) series

Examples

  • 级数？
    Zhè ge jí shǔ shōu liǎn ma?
    Does this series converge?
  • 级数。
    Wǒ men xū yào jì suàn zhè ge jí shǔ de hé.
    We need to compute the sum of this series.
  • 级数？
    Děng bǐ jí shǔ de gōng shì nǐ jì de ma?
    Do you remember the formula for geometric series?

Origin

Compound word
构词法gòucífǎ
偏正piānzhèngModifier + head

The first part narrows down the second: it says what kind of thing the head is.

级jírank
数shùnumber

级 marks the ordered degrees, and 数 marks the numbers, forming the term for a mathematical series.

Characters in this word

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

This origin belongs to the traditional form 級; 级 is its simplified writing.

Meaning part形符xíngfú
糹Written in full as糸mìthread
Sound part声符shēngfú
及
及jí級jí
Same sound today

The traditional form 級 has 糹 (thread) and 及 as a sound part; its original sense was a sequence related to silk. The simplified 级 is a later shorthand.

Open 级 →

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

This origin belongs to the traditional form 數; 数 is its simplified writing.

Meaning part形符xíngfú
攴攴pū
Sound part声符shēngfú
婁
婁lóu數shù(r)
The sound has drifted apartThe sound part was a clue two thousand years ago — it often still helps, but not always.

The traditional form 數 pairs 攴, the meaning part, with 婁, the sound part; the simplified 数 is a shorthand.

Open 数 →

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