rensa

Rensa is a Japanese noun meaning chain, linkage, or sequence. It is written with the kanji 連鎖, formed from 連 (to link or connect) and 鎖 (chain). The term denotes a series of connected items or events and appears in both everyday language and technical terminology.

In usage, rensa appears in compounds such as 連鎖反応 (rensha hannō), chain reaction; 連鎖的 (rensa-teki), chain-like or sequential; and 連鎖的伝播 (rensa-teki denpan), cascading propagation. The word is typically read rensa; when part of compounds with 反応, it is often pronounced rensha, as in rensa hannō.

In science and engineering, rensa describes processes in which one event triggers a sequence of others, including chemical chain reactions and nuclear chain reactions (核分裂連鎖反応, kakubunretsu rensa hannō). It also appears in epidemiology to describe a chain of transmission and in systems theory to discuss cascading networks, though these usages may extend beyond the strict kanji composition.

Beyond Japanese usage, rensa may appear as a transliteration or in proper nouns; however, the term remains primarily a native Japanese lexical item. The concept of a chain or cascade conveyed by rensa is widely understood across fields as a way to describe linked sequences of events or components.