Pace
Pace is running speed expressed as time per kilometer (min/km). The smaller the number, the faster the run: 5:00/km is faster than 6:00/km.
In detail
In running, pace is more convenient than speed (km/h) because training plans and race splits are built around time over distance rather than abstract km/h figures. A pace of 5:00/km means each kilometer is covered in exactly five minutes — with even pacing, multiplying pace by distance immediately gives you the finish time. On watches and in apps, pace is usually shown as "instant" (based on the last few seconds) and "average" (for the whole run) — these can differ noticeably on hilly terrain.
How to use it
Use a target pace to avoid starting too fast — the most common mistake among beginners. On uphills and downhills, pace naturally changes; for an honest comparison of effort, check your heart rate or use GAP (Grade Adjusted Pace).