The word "预计" is formed by combining two characters: "预", which means "in advance" or "beforehand", and "计", which means "to calculate" or "to plan". Their conceptual fusion creates the meaning of "to calculate or plan beforehand", which directly leads to the sense of "to estimate" or "to forecast". It is a logical semantic compound where the first character modifies the action of the second to specify a temporal and preparatory stage of calculation.