- Qualifying a sentence or clause as a whole: For all that, nevertheless, notwithstanding; yet; = but at the beginning of the sentence.
[ever adv. 8e. :] Appended to relative pronouns or advbs., and giving to them a generalized or indefinite force; = Latin -cumque. These combinations are now always written as single words: see howsoever adv., whosoever pron., etc.
How did the Compounding of the adverbs 'how' and 'ever' (into 'however') imply or produce meaning 3 above for 'however'? I ask not about the other meanings of 'however' here.
OED specified the pertinent definition (among the many) for 'ever' , but unhelpfully not for 'how'.