English Reference
noun

series

n.
US /ˈsɪɹiz/ UK /sˈiəɹiz/ se·ries

  1. 01 A2 Elementary

    a number of similar things or events that happen one after another.

    a number of things, events, or people of a similar kind or nature coming one after another.

    Simple

    The police are investigating a series of robberies that happened in the city center last week.

    In context

    The sudden collapse of the bank triggered a series of financial crises across the continent, forcing governments to intervene with emergency loans.

  2. 02 A2 Elementary

    a set of television or radio programs that have the same characters or theme.

    a set of related television or radio programmes broadcast in regular installments.

    Simple

    My favorite comedy series is returning for a third year this autumn.

    In context

    The documentary series explores the complex relationship between urban development and local wildlife preservation over the last fifty years.

    Usage

    The singular form is 'a series' and the plural form is 'two series'.

    Teacher's tip

    In British English, 'series' often means what Americans call a 'season'.

    Pitfall
    I watched a new serie last night. I watched a new series last night.

    The word 'series' is the same in both singular and plural forms. Do not remove the 's' for one show.

  3. 03 B1 Intermediate Sport

    a group of games played between the same two teams.

    a set of matches played between two teams or players, often to determine an overall winner.

    Simple

    The two national teams will play a five-match series starting next month.

    In context

    After losing the first two games, the team managed to win the series by securing victories in the final three matches.

  4. 04 C1 Advanced AcademicTechnical Math

    the sum of a group of numbers that follow a specific pattern.

    the sum of the terms of an infinite or finite sequence.

    Simple

    The teacher asked us to calculate the sum of the geometric series.

    In context

    The student struggled to determine whether the infinite series converged to a specific value or diverged toward infinity.

  5. 05 C2 Proficiency AcademicTechnical Science

    a way to group living things that are very similar, below a 'genus' but above a 'species'.

    a taxonomic rank below section but above species, used to group closely related organisms.

    Simple

    The botanist identified the new plant as belonging to a specific series within the oak family.

    In context

    The revision of the genus led to several species being reassigned to a different series based on recent genetic data.

Usage series footballdaily · series for children · series of blazes


Attested from the 1610s; borrowed from Latin seriēs, from serere (“to join together, bind”), ultimately from Proto-Indo-European *ser- (“to bind, put together, to line up”). Related to desert, insert, sermon, and sorcerer.

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

This entry
Origin ine-pro *ser-
Level A2 · Elementary
Frequency Very common
Updated