Diameter
/daɪˈæmɪtər/
Definitions
2 meaningsA straight line passing through the center of a circle or sphere, from one side to the other.
/daɪˈæmɪtər/
A straight line passing from side to side through the center of a circle or sphere.
The diameter of the tree trunk was surprisingly large.
💡 Simply: Imagine a pizza! The diameter is like a straight line that cuts the pizza right through the middle, from one edge to the other. It's the longest line you can draw inside the pizza.
👶 For kids: A line that goes right through the middle of a circle, from one side to the other!
More Examples
The scientist calculated the diameter of the planet using advanced techniques.
To calculate the area of a circle, you need to know its diameter.
How It's Used
"The diameter of the circle is 10 inches."
"The pipe's diameter is specified in the blueprints."
"The diameter of the Earth is approximately 12,742 kilometers."
The length of a straight line that passes through the center of a circle or sphere and divides it into two equal halves.
/daɪˈæmɪtər/
The length of the line that runs straight across the center of a circle.
The diameter of the Earth is quite impressive.
💡 Simply: Imagine you're cutting a cake in half perfectly. The diameter is the length of that cut, straight through the middle.
👶 For kids: How long a line is that goes right through the middle of a circle!
More Examples
The diameter of the wheel determines how far it travels with each rotation.
The engineer needed to know the precise diameter of the bore.
How It's Used
"The radius of the circle is half its diameter."
"The diameter of the pipe is 1 inch."
Synonyms & Antonyms
Synonyms
From Greek *diámetros* meaning "diameter," from *dia-* (through, across) + *metron* (measure).
The word 'diameter' has been used in geometry since ancient times.
Memory tip
Think of a straight arrow (diameter) shooting directly across the center of a circle.
Word Origin
"to measure across"