an amount of time that is allowed for a single event in a planned order of activities or events: I think I have a slot open in my diary. 1-hour/90 minute/4-hour, etc.

Subject and Verb Slots. A sentence has two primary slots for inserting content: the subject slot and the verb slot. Readers naturally focus on the words in these slots and, rightfully, sense that the main information will be in them. [subject slot] + [verb slot]