Glossary

Plain-language definitions of terms used across the HDL Group catalog — AI, Bitcoin, and wellness science.

Large Language Model (LLM)

An AI system trained on large amounts of text to generate and understand human language, such as the models behind ChatGPT or Claude.

In plain English: it's the AI behind chatbots like ChatGPT or Claude — it's read so much text that it can write and answer questions in a very human-sounding way.

Bitcoin

A decentralized digital currency and payment network that operates without a central bank, secured by cryptography and a fixed 21-million-coin supply.

In plain English: it's digital money that isn't controlled by any bank or government, and there will only ever be 21 million of them.

UTXO

"Unspent Transaction Output" — the accounting model Bitcoin uses to track ownership of coins, distinct from the account-balance model used by banks.

In plain English: instead of your Bitcoin balance being one running number like a bank account, it's made up of individual "coins" (leftover pieces from past transactions) that get combined and split when you spend.

Self-Custody

Holding your own Bitcoin or crypto private keys directly, rather than leaving assets with an exchange or third party.

In plain English: it means you personally hold the keys to your own crypto, instead of trusting an exchange to hold it for you.

Recommendation Engine

The algorithm a platform like YouTube uses to decide which content to show a given viewer, based on engagement signals.

In plain English: it's the system deciding what shows up next in your YouTube feed, based on what keeps you (and people like you) watching.

Positive Psychology

The branch of psychology studying what makes life fulfilling, as opposed to focusing only on dysfunction — the research base behind The Art of Joy.

In plain English: it's the science of what actually makes people happy and fulfilled, instead of just studying what goes wrong.

Sound Money

A monetary theory holding that a currency's value is best protected by a fixed or predictable supply, central to Bitcoin advocacy.

In plain English: it's the idea that money holds its value best when nobody can just print more of it whenever they want.

Digital Entrepreneurship

Building an income or business primarily through digital tools, platforms, and distribution rather than physical products or storefronts.

In plain English: it's building a business online — through apps, content, or digital products — instead of opening a physical shop.