Intelligent Systems Glossary

Reference · Terminology · 15 Definitions

Fifteen terms, defined the way I use them when shipping AI products with non-technical founders and cross-functional teams. I add terms as the work turns them up.

Add his coinages as entries using existing site language, e.g.: “Abstention — the model saying ‘I’m not sure about this one’ instead of bluffing. Pitched too eager, users learn to skim past it; too shy, one fluent wrong claim undoes earned trust. The threshold has to fail toward humility — the cheaper mistake.”

ML Explainability
Showing users why an algorithm made a decision, not just what it decided. Example: instead of “Risk: High,” explain “Risk: High — due to 6 failed trades in the last 18 months and 2x normal deal size.”
Feature Importance
Which inputs to the model drove the prediction most? Tools like SHAP and LIME show which factors influenced the decision. Non-technical users care: “This recommendation is based on X, Y, Z.”
Distribution Shift
When a model is trained on one type of data but deployed on a different type, it fails silently. Example: model trained on 90-second trades suddenly sees trades that take 30 minutes. It doesn’t know this is different.
Human-in-the-Loop
AI suggests, humans decide. Rather than fully automating a decision, the system shows the recommendation and lets users confirm, edit, or override. Builds trust and preserves human judgment.
Confidence Layer
The interface that communicates uncertainty. “92% confident” paired with “what data drove this” and “how would the decision change if X changed.” The difference between a user trusting and rejecting the same recommendation.

Product & Design

WCAG AA
Web Content Accessibility Guidelines Level AA is the practical baseline standard for web accessibility. It ensures your product works for users with disabilities: colour-blind users, keyboard-only users, screen reader users, and users with low vision.
Cognitive Friction
Unnecessary mental effort. “What does this button do?” or “Why is this here?” are friction points. Remove a confusing step and adoption rises.
Time-to-Value (TTV)
How long before a new user feels “Oh, I see why this is useful.” Shorter TTV = faster adoption. If TTV is 1 hour but users abandon at 15 minutes, you have a design problem.
Product-Led Growth (PLG)
No expensive sales team needed — the product itself drives adoption. Figma and Slack did this: so useful, users tell other users, virality follows.
User Experience (UX)
Not just beauty — clarity, speed, and trust. On AI products it is the layer where a right answer becomes an acted-on one.

Business & Go-to-Market

Customer Acquisition Cost (CAC)
Total marketing spend ÷ new customers acquired. If CAC is $1,000 but the customer only generates $500 in lifetime value, your unit economics are broken.
Lifetime Value (LTV)
If a customer pays $100/month for 3 years, LTV ≈ $3,600. Healthy businesses have LTV > 3× CAC. Below that, you’re losing money on every customer.
Painkiller vs. Vitamin
A painkiller is a must-have: users are already in enough pain to pay for relief. A vitamin is a nice-to-have, so adoption is slower and you have to manufacture the urgency. Painkillers are easier to sell, which is why I build those first.
Product-Market Fit (PMF)
When your product solves a real problem for a specific market and users want it badly enough to tell others. Without PMF, growth is unsustainable. With it, growth becomes effortless.
Programmatic Advertising
Instead of humans buying individual ad placements, algorithms bid on impressions in real time. It’s faster, cheaper, and more precise than manual buying — and, because it’s automated at scale, far easier to get wrong.

Last updated September 2026. I add terms as the work turns them up.