What is a verb for large?

There isn't a single verb that directly means "to be large." However, depending on the context, you could use several verbs to convey the idea of being large:

For physical size:

* Encompass: To include or surround a large area. "The vast forest encompassed the entire valley."

* Spread: To cover a wide area. "The wildfire spread rapidly, consuming acres of land."

* Extend: To reach out or continue for a long distance. "The river extends for hundreds of miles."

* Tower: To stand very high. "The skyscraper towers over the surrounding buildings."

* Bulge: To swell out or be abnormally large. "The balloon bulged with air."

For figurative size:

* Dominate: To be the most important or powerful. "The company dominates the market."

* Prevail: To be more successful or widespread than others. "The democratic party prevailed in the election."

* Expand: To increase in size or scope. "The company plans to expand its operations."

* Soar: To rise rapidly to a high level. "The company's profits soared this year."

The best verb to use will depend on the specific meaning you want to convey.