Entmoot was a gathering or meeting of Ents. An Entmoot didn't happen very often. In Fangorn Forest they were always held in Derndingle, a bowl-like valley far south of Treebeard's home. Since the Ents' language was so descriptive and "unhasty", an Entmoot could take a very long time. The Entmoot in The Lord of the Rings was held from February 30 to March 2, 3019 to decide whether the Ents should go to war against Saruman; it lasted from noon on the first day till afternoon on the third day, which was considered quick for an Entmoot. Meriadoc Brandybuck (Merry) and Peregrin Took (Pippin) were present at that Entmoot, staying with the "hasty" Ent Quickbeam.
In Dutch, an Entmoot is called Entmoet, which is similar to the Dutch word Ontmoet (to meet).