English Reference
adverb

substantially

adv.
US /səbˈstænʃəɫi/ UK /səbstˈænʃəlˌi/ sub·stan·tial·ly

  1. 01 B2 Upper Intermediate Academic

    by a large amount or to a great degree.

    to a considerable or significant extent; used to quantify a change or difference.

    Simple

    The price of the house has increased substantially since they bought it last year.

    In context

    The new environmental regulations have substantially reduced the volume of industrial waste discharged into the local river system.

    Usage

    Commonly modifies verbs of change like 'increase', 'decrease', 'improve', or 'differ'.

  2. 02 C1 Advanced FormalAcademic

    used to say that something is true in the most important ways, even if not in every detail.

    in essence or in regard to the main points; used when a statement is true for the most part.

    Simple

    The two reports are substantially the same, with only a few small differences.

    In context

    While the wording has been updated for modern readers, the legal principles remain substantially unchanged from the original 19th-century statute.

    Usage

    Often used before adjectives like 'the same', 'different', or 'unchanged'.

Usage substantially higher · substantially affect · substantially alter

Japan's Ministry of Finance says that AI adoption by businesses has already increased substantially, , external with 75% of companies now using the technology, up from 11% five years ago.

BBC News· 12 Aug 2026

A large study suggests that substantially greater benefits may require roughly 560 to 610 minutes a week—nearly 9 to 10 hours of brisk walking, running, cycling, or similar activity.

ScienceDaily· 8 Aug 2026

From substantial + -ly.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C1 · Advanced
Frequency Frequent
Updated