as mentioned earlier; as discussed previously
A fixed phrase used to refer back to something already stated in the same text or conversation. Common in formal writing, presentations, and explanations.
As mentioned earlier, this issue is very important.
As discussed previously, the new system will start next month.
A transparent combination of 前 (before), に (particle), 述べた (past form of 述べる 'to state'), and ように (as). No special etymology beyond its literal components.