The User Experience
When a student encounters a underlined glossary term, they can click on it to see the definition. A little pop up tooltip will tell the student the definition and show an image if there is one. They can also access a list of all the terms in the lesson by going to the right hand toolbar and clicking on the glossary icon. This will slide in the list of glossary terms in the lesson that they can look over.
A video depicting the two ways you can view a glossary term's definiton.
Having the experience unobtrusive was key, because we didn't want students to get distracted. Rather than open up separate tabs or new windows, we intergrated it as much as we could. This lead to the side toolbar. The secondary vertical pane that shifted out of the toolbar also served a great place to hold the table of contents, which allowed quick navigation.
The Visuals
We had a variety of concepts and objects to diagram including careers, mathematic principles, and industry‑specific terms. Fortunately, I had a library of image assets that I'd slowly created over time, making this task a little less time-intensive. However, it still required a bit more thought over how to illustrate more abstract concepts like “viable” and “hypothesize.”

Coupons

Marketing

Telephoto Lens

Entrepreneur

Critique

Revenue

Pricing Structure

Baker

Budget

Production Costs

List Price

Critically Endangered

Personal Shopper

Cost of Production

Agility

Counting Principle

Stage Manager

Median

Video Wall

Viable