The word "限于" is formed as a verb phrase through the combination of the verb "限" (xiàn), meaning "to limit" or "to restrict," and the preposition "于" (yú), which here functions to introduce the object or scope of the limitation, roughly translating to "in," "to," or "by." When combined, "限于" expresses the concept of "being limited to" or "confined within" a specific condition, range, or factor, where "限" provides the core action of limiting and "于" grammatically links that action to its target, creating a cohesive unit meaning "to be restricted by" or "to only extend as far as."