# Markets

Markets are defined by **question** which resolve based on a real-world events, such as "Will BTC close above $100,000 on December 31?" Users take a side by predicting *Yes* or *No*, and win if the question resolves in their favor.

## Outcomes

All markets consist of two sides, *Yes* or *No*. Most markets resolve to *Yes* or *No* to match, but can also resolve **non-decisively**: a tie or a result that can't be settled cleanly. A non-decisive outcome counts against the predictor: the counterparty wins.

Because Meridian Predict operates like an auction, a question's implied probability comes from how much each side stakes. See [Odds](/trading/predictions/odds-and-payouts) for how stakes map to odds and payouts.

## Taxonomy

Meridian Predict groups and labels questions in several ways to help you find what interests you. These are purely for browsing and discovery, and have no bearing on how a market is priced or settled.

* **Category**: a top-level focus area such as Crypto, Sports, Economy & Finance, Geopolitics, or Culture, Tech & Science. Browse by category to narrow to the kinds of questions you care about.
* **Group**: a bundle of related questions, such as the outcomes of a single market or the candidates in a race. Grouping is organizational; every question in a group still resolves independently as its own *Yes* / *No* market. Some groups are **negative-risk** baskets, where the outcomes are mutually exclusive and only one can resolve *Yes*; Meridian Predict labels these, but each question is still settled on its own.
* **Cluster**: a single real-world event, such as a sports match, that ties several groups together into one entity. One game, for instance, spans separate groups for the moneyline, the spread, and the totals; a cluster brings them together so they can be ranked by their combined volume.
* **Tag**: a freeform label on a question (a team, topic, or person) used for finer-grained discovery. You can filter by tag, and the most popular tags are surfaced for browsing.

## Status & Timing

Each question is either **open** or **resolved**:

* **Open**: the question has not resolved yet. You can still take a position.
* **Resolved**: the underlying outcome is final. Winning positions can be redeemed and no new positions are taken. See [Resolution & Settlement](/trading/predictions/resolution-and-settlement).

A question's end time is an **estimate**, not a fixed deadline: a question resolves when the underlying market it is drawn from is settled, which can happen earlier or later than the displayed date. See [Resolution & Settlement](/trading/predictions/resolution-and-settlement) for how this works.

:::info
Meridian Predict surfaces questions from established prediction markets. The available markets, categories, and estimated resolution dates are determined by the underlying sources and may change over time.
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