English Reference
adjective · noun

supplemental

adj. · n.
US /ˌsəpɫəˈmɛnəɫ/ UK /sˌʌplɪmˈɛntəl/ sup·ple·men·tal UK spelling supplementals

  1. 01 B2 Upper Intermediate Academic

    adj.added to something else to improve it or provide more information.

    adj.serving as a supplement; providing additional support, information, or reinforcement to a primary element.

    Simple

    The teacher gave us supplemental reading materials to help us understand the topic.

    In context

    The researchers provided supplemental data in the appendix to support their controversial findings regarding the new drug's efficacy.

    Usage

    Usually placed before the noun it modifies.

  2. 02 C1 Advanced Technical

    adj.describes something that happens outside of a normal schedule, like an extra flight.

    adj.referring to services or items provided outside of a standard schedule or regular provision.

    Simple

    The airline added a supplemental flight to handle the holiday crowds.

    In context

    The charter company operates supplemental air carrier services during peak seasonal demand to alleviate pressure on commercial routes.

  3. 03 B2 Upper Intermediate

    n.a thing that is added to something else.

    n.an item, document, or amount added to a larger whole to complete or enhance it.

    Simple

    The new law included a supplemental for emergency school funding.

    In context

    The committee approved a budget supplemental to cover the unforeseen costs of the infrastructure repairs.

  4. 04 C1 Advanced FormalTechnical Law

    n.extra money given by a government for a specific project.

    n.a formal requisition or piece of legislation that provides additional funding for an existing program.

    Simple

    Congress passed a supplemental to help the city after the flood.

    In context

    The defense department requested a supplemental to ensure the continued operation of the peacekeeping mission through the end of the fiscal year.

In fact, gig work may be supplemental, but it isn’t always optional.

The Conversation· 7 Aug 2026

From supplement + -al.

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

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated