The phrase "gather momentum" implies that something is steadily growing in strength or power. Some synonyms for this phrase might include "pick up speed," "build momentum," "gain traction," "develop force," or "gather steam." These phrases all suggest forward movement and increasing power, and can be used to describe anything from a political movement to a sports team. When we say that something is gathering momentum, we mean that it is becoming more and more influential or powerful over time. This can be an exciting and motivating feeling, as we watch our efforts start to pay off and our goals begin to take shape.