- the CHAIN programming language (if we really have such questions, I'd recommend retagging to chain-lang)
- the process of chaining. The tag wiki said: "combine multiple processes or functions together to create a larger process or function". Sounds a bit like composition or piping to me.
- the practise of method chaining (seems to be the most popular). This is what the tag wiki describes, though the excerpt says that method-chaining should be used instead. We also have chaining with a matching tag wiki, these should likely be merged.
- the data structure chain - a linked list in effect. Used e.g. in prototype-chain, keychain, toolchain, markov-chains, chain-of-responsibility, certificate chains, scope-chain, etc.
What do you think? Do we need a separate tag for the generic data structure? If you find more programming-relevant meanings, please edit this question. And of course please help with the cleanup, though there aren't that many questions (<300).