summons

The noun form is deceptive because it ends in -s, but it is a singular count noun. A single official order is a summons, and multiple orders are summonses. This often leads to errors where speakers treat it as a plural noun or an uncountable mass.

As a verb, the word carries a strong sense of authority and formality. It is rarely used in casual social contexts; instead, it implies a hierarchical relationship where the person issuing the order has the legal or professional power to compel the other's presence.