To predominate means to be the most common, powerful, or noticeable thing in a situation. When something predominates, it stands out above everything else because there's more of it or it has more influence.

In a forest where oak trees predominate, you'll see oaks everywhere you look, far outnumbering the maples and pines. If rainy weather predominates during your beach vacation, most days are wet rather than sunny. When one player's strategy predominates in a chess match, that approach controls how the game unfolds.

The word often describes what takes up the most space, time, or attention. In a classroom discussion about ancient Rome, if military topics predominate, students spend most of their time talking about battles and armies rather than art or daily life. If nervousness predominates during a student's piano recital, that feeling overshadows any excitement or confidence they might also feel.

Predominate is closely related to dominant, and both suggest being number one in some way. Predominate specifically emphasizes being the most prevalent or influential compared to alternatives: the main thing going on in a situation.