radi

IPA/ɹˈeɪdi/
KK[rˈɑdi]IPA/rˈɑːdiː/

radi — combining form

1. used before a noun to refer to energy that travels in the form of waves or parti

1.構詞成分B1
釋義

used before a noun to refer to energy that travels in the form of waves or particles, such as light, heat, or X-rays

例句

The scientist measured the solar radiation reaching the Earth's surface.

compound: solar radiation

Infrared lamps use radiant heat to warm people directly without heating the air.

compound: radiant heat

文法句型

radi- + noun (e.g., radiation, radiance)

用法筆記

Most words using this sense are technical or scientific. The related verb 'radiate' and noun 'radiation' are the most common forms in everyday English.

常見錯誤

❌The sun emits radi heat.
✅The sun emits radiant heat.
💡The combining form 'radi-' appears in the word 'radiant', not as a separate word 'radi'.

2. used before a noun to refer to the process of unstable atoms releasing energy or

2.構詞成分B1
釋義

used before a noun to refer to the process of unstable atoms releasing energy or to materials that produce such energy

例句

The hospital uses a radioactive substance to find tumours inside the body.

compound: radioactive substance

Lakshmi studied the radioactivity levels near the old power plant for her research project.

compound: radioactivity levels

文法句型

radi- + noun (e.g., radioactive, radioactivity)

用法筆記

Commonly appears in 'radioactive' (adjective) and 'radioactivity' (noun). In news reports, 'radioactive material' is a frequent collocation.

常見錯誤

❌The water is radi active.
✅The water is radioactive.
💡'Radioactive' is one word, not two.

3. used in medical words that refer specifically to the element radium or to X-ray

3.構詞成分B2
釋義

used in medical words that refer specifically to the element radium or to X-ray technology as a clinical tool for diagnosing and treating illness

例句

Hugo attended ten sessions of radiotherapy after the operation on his lung.

compound: radiotherapy

The radiologist examined the X-ray images and marked a small shadow near the rib.

compound: radiologist

文法句型

radi- + noun (e.g., radiotherapy, radiology, radiography)

用法筆記

This sense is used specifically in medical and clinical contexts involving the element radium or X-ray imaging and treatment. Unlike sense 1 (RADIANT ENERGY / RADIATION), which covers the general physical phenomenon of energy emission, sense 3 is limited to concrete applications of radium and X-ray technology in healthcare settings.

4. used in words relating to the technology of sending and receiving sound or signa

4.構詞成分A2
釋義

used in words relating to the technology of sending and receiving sound or signals through the air using electromagnetic waves

例句

Kenji switched on the car radio and listened to the morning traffic report.

compound: radio (simplified form of radiogram)

The ship sent a radiogram asking for urgent medical help during the storm.

compound: radiogram

文法句型

radi- + noun (e.g., radio, radiogram, radiowave)

用法筆記

The word 'radio' itself is the most common form of this combining form. 'Radio' is so frequently used that most learners do not recognise it as containing a prefix.

常見錯誤

❌I heard it on the radi.
✅I heard it on the radio.
💡The combining form appears inside 'radio', not as 'radi' alone.

5. used in medical words relating to the radius, which is the shorter bone on the t

5.構詞成分C1
釋義

used in medical words relating to the radius, which is the shorter bone on the thumb side of the lower arm that connects the elbow to the wrist

例句

The radiocarpal joint connects the radius bone to the bones of the wrist.

compound: radiocarpal joint

A fracture of the radial head near the elbow makes turning the forearm painful.

compound: radial head (adjective form)

文法句型

radi- + noun (e.g., radiocarpal)

用法筆記

This sense is limited to medical and anatomical vocabulary. The noun 'radius' (the actual bone) is more common than compounds like 'radiocarpal'.