累加 means 'to add up repeatedly' or 'to accumulate through addition'. It combines 累 (lěi), meaning 'accumulate' or 'pile up', and 加 (jiā), meaning 'to add'. Together, they emphasize the process of incrementally summing quantities—often over time or across multiple instances—rather than a single addition. This verb is commonly used in mathematical, financial, statistical, and technical contexts, such as calculating totals from repeated inputs, tracking cumulative scores, or describing progressive growth.

Unlike simple addition (加), 累加 implies continuity and repetition: each new value contributes to an ever-growing total. It frequently appears with measure words or time markers (e.g., 每天、每次、逐次) and often pairs with nouns like 数值 (numerical values), 分数 (scores), 或 金额 (amounts). While it can be used transitively ('to accumulate X'), it’s also common in passive or abstract constructions (e.g., 数据被累加, 'data is cumulatively added').