👉 The word 'abovestairs' refers to a group of pipes, valves or other equipment used in steam engines above the boiler. It is commonly found in old-fashioned steam locomotives and steam turbines.
👉 The word "abovesaid" refers to something that has already been said in a particular context. It does not imply that the speaker is saying something above it, but rather that they are speaking about what has already been mentioned or discussed in that context.