English Reference
adjective · noun

proportional

adj. · n.
US /pɹəˈpɔɹʃənəɫ/ UK /pɹəpˈɔːʃənəl/ pro·por·tion·al

  1. 01 B2 Upper Intermediate Math

    adj.changing in size, amount, or degree according to something else.

    adj.corresponding in size or amount to something else; maintaining a constant ratio as another variable changes.

    Simple

    The punishment should be proportional to the crime.

    In context

    The weight of the object is directly proportional to its mass, meaning that as mass increases, the weight increases at a constant rate.

    Usage

    Often followed by the preposition 'to'.

  2. 02 C1 Advanced Technical Computing

    adj.describing a style of printing where different letters take up different amounts of space.

    adj.relating to a typeface where characters have varying widths based on their natural shape, rather than a fixed width.

    Simple

    Most books use a proportional font because it is easier to read than a typewriter style.

    In context

    Proportional spacing allows the letter 'i' to occupy significantly less horizontal space than the letter 'm', resulting in a more aesthetically pleasing text block.

    variable width
    monospacefixed width
  3. 03 C2 Proficiency Archaic Math

    n.an old word for a portion or a ratio.

    n.a value or quantity that exists in a specific ratio to another.

    Simple

    The old text discussed the mathematical proportional of the two circles.

    In context

    In his early seventeenth-century treatise, the author calculates the exact proportional required to balance the architectural load.

    Teacher's tip

    This noun sense is extremely rare in modern English; learners should use 'proportion' or 'ratio' instead.

Usage directly proportional · proportional to

Dearden feels half a dozen hits is proportional to what would be expected.

The Guardian· 7 Sept 2026

In the UK, the 2024 general election produced the country's least proportional result on record, with Labour securing 63% of the seats after receiving 33.7% of the vote.

ScienceDaily· 2 Aug 2026
This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated