diameter - Master This Word
Master this word with our 5-step learning method – Learn English in English
diameter Word Meanings
- The straight line passing through the center of a circle.
- The length of this line.
- A measure of width across a circular object.
diameter Example Sentences
Example sentences are the start of understanding. Don't rush to memorize. First feel how the word works in a sentence.
diameter Phonetic & Pronunciation
UK
/daɪˈæmɪtə/
US
/daɪˈæməter/
diameter Word Etymology
Dia- = through + -meter = measure. Origin: Greek → Latin → English. Imagine a giant circle drawn on the ground, and a surveyor measuring its width with a long stick that spans across it, determining its 'diameter'.
Note 1: These definitions and etymologies are not standard dictionary definitions, but extended explanations provided to help with memorization and understanding of the actual application of words. Through this background information, we strive to make words more vivid and easier to understand, and help you remember their meanings in real life.
Note 2: LexiTalk designs the learning flow around the linguistics principle of “Comprehensible Input.” When learners encounter material that is slightly above their level but still understandable from context, the brain naturally absorbs the language. That’s why we keep every word inside authentic contexts, using examples and associations to help you understand it and use it flexibly.
Read the FAQ explanation of Comprehensible InputReal Context
Diameter is a geometry term for the straight line that passes through the center of a circle and touches the circle at two points. It is also the length of that line, which is twice the circle's radius. In everyday language, diameter is used to describe the width of circular objects, such as a disk, a steering wheel, or a wheel, measured across its center. Learners often confuse diameter with radius or circumference. In math, diameter is often denoted by d and equals 2 times the radius.
Usage Reminders
- Remember d = 2r. Distinguish diameter from radius and circumference. Visualize the circle with a line through the center. Use real objects to measure across. Look for diagrams where diameter is labeled. Practice with diameter problems.
Common Misconceptions
- Diameter equals radius
- Diameter equals circumference
- Diameter is the same as the circle's boundary
- Any line drawn across a circle is a diameter
- Diameter is the distance around the circle
Thinking Differences
In English, diameter is a precise geometric term. Learners often confuse it with radius or circumference because the words all involve measurements across or around a circle. English uses compact terms like diameter and symbol d in formulas, so a quick mental check (d = 2r) helps avoid mistakes.
Learning Tips
- Visualize the circle with a line through the center
- Remember d = 2r and practice with formula problems
- Distinguish width (diameter) from distance from center to edge (radius)
- Label diagrams clearly: mark diameter with d
- Use real objects (coins, wheels) to measure across
- Solve quick-check questions comparing diameter, radius, and circumference
5-Step Learning Method - Learn English in English
Step 1: Meaning
What is the meaning of the word 'diameter'?
A.A straight line passing from side to side through the center of a circle or sphere
B.A point where two lines meet
C.The distance between two parallel lines
D.A line that extends infinitely in both directions
Step 2: Usage
In which of the following sentences is the word 'diameter' used correctly?
A.She measured the diameter of the rectangle to find its area.
B.The diameter of the tree trunk was covered in colorful paint.
C.He drew a diameter to bisect the circle into two equal parts.
D.The students were learning about the diameter of DNA strands.
Step 3: Similar Words
Which of the following words is a synonym of 'diameter'?
A.Radius
B.Circumference
C.Diameter
D.Diameter
Step 4: Opposite Words
Which of the following words is an opposite of 'diameter'?
A.Width
B.Curvature
C.Diameter
D.Circumference
Step 5: Mastery
How would you explain the concept of 'diameter' to someone who has never heard of it before?
A.Diameter is the measurement of how wide a circle is from side to side.
B.Diameter is the distance around the edge of a circle.
C.Diameter is the length from the center of a circle to its edge.
D.Diameter is a special line that divides a circle into two equal parts.
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