Every field has a vocabulary, and the vocabulary matters more than it looks.
Terms like attractor, ergodicity, phase transition and power law are not decorative imports from physics. They are the precise language required to describe things classical finance cannot properly name — the difference between behaviour that is bounded but unpredictable and behaviour that is merely random, between structure and uniformity. Without that language, the argument about how markets actually work cannot be made with the necessary precision.
So I have compiled the terms used across the essays and research on this site into a single reference. Seventy-one of them, across four sections.
Complexity Science — the explanatory framework. Emergence, criticality, reflexivity, self-organised criticality.
Market Structure — how that complexity shows up in price. Fat tails, fractals, the Hurst exponent, inelastic impact.
Systematic Trading — the practical work. Position sizing, convexity, ergodicity, the metrics worth using and the ones that mislead.
The Turtle Lexicon — the plain-spoken language of the classic trend follower. Closed equity, small bets, vows.
Each definition is written for the practitioner rather than the textbook: someone who needs to understand a concept well enough to act on it. Where a direct line exists, the entry points to the essay or series in The Vault where the idea is worked through properly.
It is free, it is 26 pages, and it needs no email address.
Download the Glossary of Complexity and Markets (PDF)
It is also a living document. New series introduce new terminology, and entries are updated as the framework develops. If a term you would expect to find is missing, tell me and it goes in the next edition.
Richard Brennan writes on systematic trading, complex adaptive markets, and the philosophical foundations of trend following at atstradingsolutions.com. His books include The Fractals of Finance, Complex Adaptive Markets, Carved by Impossibility and The Aussie Turtles Trend Following Guide.
Want to explore why structure exists at all?
Carved by Impossibility: What Remains When Everything Else Is Eliminated
The book explores the architecture of constraint, emergence, and reality itself, and what it means for how we understand markets, life, and the universe.
Available now on Amazon in paperback, hardcover, and Kindle.
Want the theoretical foundation for why trend following works?
The Fractals of Finance: Determinism, Adaptation and the Geometry of Markets bridges complexity science with practical trading implementation. With a foreword by Jerry Parker, original Turtle Trader.
Available now on Amazon in paperback, hardcover, and Kindle.
Want a practical field manual for trading trends and capturing outliers?
The Aussie Turtles Trend Following Guide: A Field Manual for Hunting Outliers adapts the timeless principles of the original Turtle traders into a systematic, rules-based approach for modern markets. Co-authored with Adam Havryliv.
Available now on Amazon in paperback, hardcover, and Kindle.