Here are some commonly talked about gaps in the Interstate Highway System that any roadgeek should at least have a cursory understanding of:
Breezewood: a small gap in I-70 in southern Pennsylvania where it leaves the Pennsylvania Turnpike and travels on surface roads for a short period of time. Commonly gaps in other routes are described as "Breezewood-like".
Bella Vista Bypass: a bypass of Bella Vista, AR on I-49 at the Arkansas-Missouri border that is being constructed now.
I-95/Penn Turnpike Interchange: before 2018, I-95 had a gap in the Trenton, NJ area as there was no direct connection between it and the Pennsylvania Turnpike (today there is a direct connection at the I-276/I-295/I-95 interchange). The interchange is an important American road milestone in the past 10 years.
I-585: In Spartanburg, SC, I-585 currently does not connect to its parent interstate, I-85, as I-85 was rerouted onto a bypass route.
And here are some Texas terms (with examples!) you should know:
Feeder Roads: basically just the Houston word for a frontage road. These run alongside freeways and usually have businesses on them.
Example:Texas U-turns: when feeder roads intersect normal roads, you'll find these letting traffic on the feeder roads make a U-turn without sitting through 2 traffic lights.
Example:Stack Interchange: a high volume type of interchange that is used very much in Texas. Generally has 4 or 5 levels of roads.
Example:"Poor Boy": a four lane road with only a center line separating oncoming traffic. Texas used to love these, as they were cheap to build.
Example: