English Reference
adjective · adverb · noun

prior

adj. · adv. · n.
US /ˈpɹaɪɝ/ UK /pɹˈaɪɐ/ pri·or UK spelling priors

  1. 01 B2 Upper Intermediate Formal

    adj.happening or existing before something else.

    adj.existing or occurring before in time, order, or importance.

    Simple

    The athlete had no prior experience in this type of competition.

    In context

    The merger was cancelled because the company had a prior agreement with a different international partner.

  2. 02 B2 Upper Intermediate Formal

    adv.used with 'to' to mean before a specific time or event.

    adv.functioning as a compound preposition when followed by 'to', indicating temporal precedence.

    Simple

    Please sign these documents prior to your appointment on Tuesday.

    In context

    Prior to the implementation of the new software, all staff members must complete a mandatory training module.

    Pitfall
    He arrived prior the meeting. He arrived prior to the meeting.

    When using 'prior' as an adverb meaning 'before', you must include the word 'to'.

  3. 03 C2 Proficiency Formal Religion

    n.a man who is the head of a religious house, like a monastery.

    n.a monk who is the head of a religious house or second in authority to an abbot.

    Simple

    The prior led the monks into the chapel for their morning prayers.

    In context

    The prior was responsible for the daily administration of the monastery, ensuring that both spiritual and temporal duties were fulfilled.

  4. 04 C1 Advanced American EnglishInformal Law

    n.a person's past crimes or times they were arrested.

    n.a previous criminal conviction or arrest on an individual's record.

    Simple

    The police checked his file and saw he had several priors for theft.

    In context

    The judge took the defendant's lack of priors into account when deciding on a more lenient sentence.

    Usage

    Usually used in the plural form 'priors'.

  5. 05 C2 Proficiency TechnicalAcademic Math

    n.an initial guess or calculation made before new information is collected.

    n.a prior probability distribution representing the likelihood of an outcome before new evidence is taken into account.

    Simple

    The researcher updated the prior after seeing the results of the first test.

    In context

    In Bayesian inference, the prior is combined with the likelihood function to determine the posterior distribution.

Usage prior research · expenditure prior

Lynda Rousseau and her husband Joe had lived in Texas for 19 years prior to retiring in their home country of Canada.

BBC News· 14 Aug 2026

Prior research on this topic focused on small geographic areas and short timescales.

Phys.org· 12 Aug 2026

From Middle English Prior, Priur (surname), from Middle English prior, priour (“prior”). More at prior.

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

This entry
Origin Middle English prior
Level B2 · Upper Intermediate
Frequency Very common
Updated