Types of scientific events: conference, congress, symposium

Someone forwards you a call for papers. The banner says “XIV Congress”, the call mentions three symposia, a satellite workshop, and a plenary session, and the submission form asks whether you want an oral or a poster slot. All of that is one scientific event. Whether you are organizing it or deciding if it is worth the trip, it helps to know what each word is promising.

This guide sorts the vocabulary into three layers: the umbrella events, the sessions inside them, and the parts of the schedule that are not scientific presentation at all. One warning up front: there is no enforced academic taxonomy for these labels. Industry glossaries exist, but scientific communities name their meetings by field, country, and tradition, and usage varies accordingly. What follows is how the words are generally used in English-language academia, and where the ground is genuinely unstable, this guide says so instead of inventing a rule.

The umbrella events

These are the words that go on the banner. Four axes separate them: scale, breadth of scope, who convenes the scientific event, and how much of the schedule is presentation versus discussion.

Format	Typical scale	Scope	Who convenes
Conference	Hundreds to thousands	Broad, several themed tracks	Society, institution, or standing steering committee
Congress	Large, often thousands	Broad, an umbrella theme with many tracks	Society, federation, or national/international association
Symposium	Dozens to a few hundred	One focused topic	Research group, committee, or a track inside a larger event
Workshop	Dozens	One problem, often unresolved	Small organizing group, frequently as a conference satellite
Colloquium	A dozen to a few dozen	Varies widely	Department, institute, or research group
Seminar	Small, often a room	One topic, often recurring	Department, lab, or graduate program

Conference and congress

This is the pair that causes the most confusion, and the honest answer is that they overlap almost completely.

The tendency in English: a congress is a large, periodic meeting convened by a society or a federation, often international, often the year’s principal gathering of a field. A conference is the general-purpose English word for a scientific meeting, applied from a 60-person regional event up to a 15,000-person annual meeting.

The tendency breaks constantly. In Spanish- and Portuguese-speaking academia, “congreso” and “congresso” are simply the default word for what an English-speaking community would call a conference, and the event’s English name keeps “Congress”. In much of computing, the flagship international meetings are conventionally called conferences, not congresses. The noun tells you about the community’s tradition more than about the event’s size. Read the call for papers.

One difference does hold: a congress usually belongs to a society with members, and the society’s general assembly travels with it.

Symposium

A symposium is narrower than a conference. It gathers researchers around one focused topic, usually with the intent that the whole room can follow the whole program, which a large conference does not attempt.

Two uses coexist, and both are correct. A symposium can be a standalone event, with its own call for papers, peer review, and proceedings. Or it can be a track inside a larger congress: a themed block of sessions proposed by a group, with its own chair, running alongside other symposia. That is why one congress program can list a dozen symposia without contradiction.

Workshop

The distinction that tends to hold is participation. A workshop usually emphasizes focused interaction, practical learning, or collaborative problem-solving more than a conventional paper session does, and the schedule protects time for that. In some fields, especially computing, workshops also include peer-reviewed paper presentations and their own proceedings. Most workshops are small; nothing about the word requires it.

Workshops attached to a conference, usually the day before or after the main program, are standard in many fields, often with their own lightweight call for papers and, increasingly, their own proceedings.

Colloquium and seminar

Colloquium is the least stable term in English. In many departments it names a recurring research-talk series: an invited speaker, an hour, faculty and graduate students, no call for papers, no proceedings. Elsewhere it names a formal specialist meeting, and a few fields use it as a plain synonym for symposium. Read the program, not the noun.

A seminar brings a relatively small group together for study, training, or discussion. In a graduate program it is often the recurring meeting where work in progress gets taken apart constructively; in other settings it is a one-off scientific event open to registration, closer to a small symposium. The loose distinction is that a colloquium tends to bring in an outside speaker.

The sessions inside the event

Once the event opens, these are the formats on the program.

Keynote and plenary. A plenary session is intended for the full audience and typically has nothing scheduled against it. A keynote is a featured talk, usually by an invited figure framing the theme. Keynotes often occupy plenary slots, which is why the words get swapped, but plenary is about the slot and keynote is about the talk.

Invited talk. A speaker the committee approached directly, rather than one who came through the call for papers. Programs commonly give invited talks more time than contributed ones, but how much time and billing they get is the program’s choice.

Oral session (contributed talks). The backbone of the program: papers accepted through the call for papers and peer review, grouped by theme, 10 to 20 minutes each plus questions, run by a session chair who guards the clock. At a large congress several run at once, which is what “parallel session” means.

Poster session. Authors stand beside their work and talk to whoever stops. At many events posters clear the same peer review and land in the same proceedings as the oral papers. Treating them as a consolation prize for rejected talks is a choice some committees make; it is not what the format is for.

Panel discussion and roundtable. A panel brings a few speakers into a moderated discussion, usually with audience questions: sometimes to surface disagreement, sometimes to compare perspectives or synthesize practice. Roundtable is often a synonym, and often not: in its stricter sense every participant has an active role, there is no separate audience, and the numbers are capped so that discussion stays possible.

Birds of a feather (BoF) and breakout sessions. A BoF is a self-organized, low-ceremony meeting on a narrow shared interest, common in computing: no call for papers, no review, no proceedings; someone books a room and a topic, and whoever cares turns up. A breakout session is broader: any smaller session formed by dividing the main audience, and it can hold talks, panels, exercises, or facilitated discussion. A lot of the useful conversation at large conferences happens in both.

Tutorial or short course. Structured teaching by a subject expert, often scheduled before the main program. Length, format, and registration arrangements vary; a separate registration is common.

Hackathon and satellite meeting. A hackathon is a workshop with a deliverable and a deadline. A satellite meeting is an affiliated meeting scheduled alongside or near the main conference, often co-located but sometimes separately organized and registered, which is how a lot of collaboration gets scheduled without a second flight.

The parts that are not presentation

Trade show and exhibition. An exhibition shows something, and it can be scientific in its own right: equipment, research results, a collection, an institutional presence. A trade show is the reliably commercial one, organized around exhibitor stands, and it frequently funds the rest of the program. Both belong to the scientific event even when they sit outside the program of talks.

Forum. Lower on technical content, higher on engagement. A forum gathers people around a problem, often one with a policy or public dimension, and the moderators exist to draw out disagreement rather than to keep the schedule. It is usually open beyond the specialists.

General assembly and business meeting. This matters to any scientific society, and it is the piece most often left out of event planning. Assemblies, elections, and bylaw votes are often scheduled alongside the annual congress for the obvious reason: it is the moment when much of the membership is already in the building. Their timing, agenda, and voting rights, though, come from the society’s statutes, not from the event program, and that is the point organizers miss: conference registration and voting eligibility are separate records. Treating them as one list is where societies lose track of their own membership. Keeping membership and event operations in one ecosystem keeps that distinction intact.

What this means when you are the one organizing

The names promise a shape of conversation, and the community reads them fluently. But the label on the banner is the last thing to worry about, because the call for papers, the program, and the proceedings are what people judge.

• Name the scientific event by what it does. Size and scope create expectations, but they do not determine the label: a focused 80-person meeting can defensibly be a symposium, a workshop, or a small conference.
• Tradition picks between the big words. A broad multi-track meeting can be a conference or a congress, and choosing between the two is a matter of your community’s and your society’s tradition, not of a size threshold.
• Whatever is on the banner, the submissions need the same infrastructure. Call for papers, peer review, session assignment, and publication do not change because the noun changed. What changes is scale.
• The output outlives the event. Posters, contributed talks, and symposium papers all deserve to become proceedings with DOIs, permanent and citable. Galoa, a Crossref Sponsor since 2015 and an ORCID institutional member since 2025, makes sure that record leaves your event aligned with the global indexing standard, authorship correctly attributed.

The vocabulary is not going to standardize, and it does not need to. What matters is that the event delivers what its name led people to expect: a workshop where people actually work, a symposium where the room can follow every talk, and a congress that leaves behind a scientific record worth citing.