Definition

1. Noun:
   • A fixed or unchanging amount: A "constant quantity" refers to a specific numerical value or amount that remains the same and does not change under given conditions.
   • An invariant value: In mathematics and science, it is a quantity that is held fixed during a calculation, experiment, or discussion, in contrast to a variable quantity.

Usage Examples

• Noun:
  • In this equation, 'c' represents a constant quantity, while 'x' is the variable.
  • The speed of light in a vacuum is a fundamental constant quantity in physics.
  • For the experiment to be valid, we must keep the pressure as a constant quantity.

Advanced Usage

• "To treat as a constant quantity": To consider or handle a value as fixed and unchanging within a specific context.
  • When differentiating, you can treat any number multiplied by the variable as a constant quantity.
• "To hold a quantity constant": To deliberately maintain a specific parameter at a fixed value.
  • The researchers held the temperature as a constant quantity to observe the effect of pressure alone.

Variants and Related Words

• Constant (n/adj): As a noun, it directly refers to a constant quantity. As an adjective, it describes something that does not change.
  • The gravitational constant is a key value in calculations. (n)
  • He drove at a constant speed. (adj)
• Invariant (n/adj): A quantity or property that remains unchanged under a set of transformations.
  • The total energy in a closed system is an invariant.

Synonyms

• Fixed value: A number or amount that is set and does not vary.
• Parameter (when held constant): A numerical factor that defines a system, often held constant in an analysis.

Related Phrases

• Constant of proportionality: A specific type of constant quantity that relates two variables that are directly proportional.
  • In the equation y = kx, 'k' is the constant of proportionality.
• Physical constant: A constant quantity that appears in the laws of physics, such as the gravitational constant or Planck's constant.

Related Idioms

• (To be) a constant: Used figuratively to describe a person or thing that is always present and unchanging.
  • Amidst all the change in the company, her dedication was a constant. (Note: This uses the related word "constant," not the phrase "constant quantity.")

Noun

1. a quantity that does not vary