A Runaway Gap, also known as Measuring Gap or Running Gap, is a commonly used technical analysis term. This is a gap that occurs after a breakaway gap during bullish or bearish trends.
This gap type is typically considered as an acceleration in the current trend, and is best described as a gap caused by a sudden increase/decrease in interest for a stock. Runaway Gaps may or may not show an eventual gap fill. That said, they fill more often than not.
Here's an example of a Runaway Gap in the middle of an uptrend on a 1 year MRVL chart for visual reference purposes: