切点 (qiē diǎn) — (geometry) point of tangency, point of contact

Definition

In geometry, 切点 is the exact point where a tangent line touches a curve or where two tangent curves meet. Used in technical/mathematical contexts rather than everyday speech.

noun
(geometry) point of tangencypoint of contact
Measure word · 个

Examples

  • 切点。
    Yuán hé zhí xiàn xiāng jiāo yú yí gè qiē diǎn.
    The circle and the line intersect at a point of tangency.
  • 切点。
    Liǎng gè yuán zài qiē diǎn chù xiāng qiē.
    The two circles are tangent at the point of tangency.
  • 切点。
    Qiú pāo wù xiàn yǔ zhí xiàn de qiē diǎn zuò biāo.
    Find the coordinates of the point of tangency between the parabola and the line.

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.

切qiètangent
点diǎnpoint

切 names the tangent action and 点 marks the point, together giving point of tangency.

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.

Meaning part形符xíngfú
刀刀dāoknife
Sound part声符shēngfú
七
七qī切qiè
The sound has drifted apartThe sound part was a clue two thousand years ago — it often still helps, but not always.

In 切, the 刀 (knife) part is joined to 七, which gives the sound.

Open 切 →

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 點; 点 is its simplified writing.

Meaning part形符xíngfú
黑黑hēiblack
Sound part声符shēngfú
占
占zhàn點diǎn(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 點 pairs 黑 (black) with 占 for its sound; the simplified 点 is a later abbreviation.

Open 点 →

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