Weird. For me, every Google result for [entmoot] is appropriate and basically gives the answer to your question I would have given. It's a Lord of the Rings reference.

Right - I understood that it was the walking tree from Lord of the Rings. But, what does it mean for Consul to hold a walking tree?

Is it something like: "Consul bears a heavy weight (has a lot of responsibility and so responds slowly)"?

A walking tree is an Ent. A meeting of Ents, with ponderous deliberation — ponderous on _Ent_ timescales, that is — is an Entmoot.

Ohhhh. Their clocks run slowly. A lot of time passes between events. Totally makes sense. Thanks!