Ultra means extreme or beyond the usual limits. When something is ultra-modern, it's pushing the boundaries of what's cutting-edge, featuring the most advanced technology or design available. When a runner completes an ultramarathon, they're running far beyond the standard 26.2-mile marathon distance, sometimes 50 or even 100 miles.

You'll often see it attached to other words to show that something goes further than normal: ultra-sensitive skin reacts more intensely than regular sensitive skin, and an ultra-lightweight backpack weighs less than other lightweight packs.

In everyday speech, people sometimes use ultra as shorthand for anything extremely intense. If your friend's mom is ultra-strict about homework, she's stricter than most parents. If a roller coaster is ultra-fast, it's faster than other fast coasters.

The word can also stand alone as a noun. In sports, an ultra is someone who competes in ultramarathons or other extreme endurance events. These athletes train their bodies and minds to go beyond what most people think is possible, taking on distances that would take most people an entire day to walk.