弧度 (hú dù) — radian (unit of angular measure)

Definition

A unit of angle measurement equal to about 57.3°, where 2π 弧度 make a full circle. Used in math and science, not in everyday descriptions of angles.

classifier

radian (unit of angular measure)

弧度57.3。
Yí gè hú dù dà yuē děng yú 57. 3 dù.
One radian is approximately equal to 57.3 degrees.
弧度。
Zhè ge jiǎo de dà xiǎo shì sān hú dù.
The size of this angle is three radians.
π弧度。
Bàn yuán de jiǎo dù shì π hú dù.
The angle of a semicircle is π radians.

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.

度dùmeasure

弧 gives the idea of an arc and 度 of a measure, so the word names the measure of an arc.

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.

弓瓜弧

Meaning part形符xíngfú

Sound part声符shēngfú

瓜

The sound has drifted apartThe sound part was a clue two thousand years ago — it often still helps, but not always.

弧 uses 弓 (bow) to show a wooden bow or a curve like a bow, and 瓜 for the pronunciation.

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

Sound part声符shēngfú

石

The sound has drifted apartThe sound part was a clue two thousand years ago — it often still helps, but not always.

度 has 又 (hand) and a changed form of 石; 石 gives a related sound, and the hand is tied to using the hand as a reference for measurement.

Appears in