Often with monoliths, once they go into production service at scale, the deployment can be "3 days, arranged 4 weeks in advance, requiring 9 sign offs including one VP"
I would call that a megalith, and not to be cute but to give a sense of scale which is useful. I think there is a point in which a monolith grows so big that is painfully obvious that size became an obstacle greater than the benefits.
Pain tolerance differs so the label gets applied at different sized monoliths.