Another word that has undergone a similar development is fustian. In its earliest sense
[4.] fustian is 'a fabric made from cotton and linen', but like bombast it too is now used to mean 'pretentious speech or writing'.
The word itself is from [3.] Medieval Latin fustaneum, whose origin is disputed. One account traces it to [2.] Latin fustis 'club, staff', as a translation of
[1.] Greek xylinon, literally meaning 'wooden' (from xylon, 'wood, club') but applied to cotton.
That such an origin is at least semantically possible is shown by another Medieval Latin term referring to cotton, lana de ligno, literally 'wool of wood'. Such a conception lies at the basis of the German word for cotton to this day, Baumwolle, literally 'tree-wool'. Another account de- rives fustaneum from the Cairo suburb Fostat (Arabic fusṭāṭ), where fus- tian is said to have been manufactured. Even on that route we wind up back at Latin, since fusṭāṭ, literally 'camp', comes (via Greek transmission) from Late Latin fossatum 'ditch, fosse'. See also DENIM.
What underlying semantic notions connect:
1 and 2 (i.e. 'wooden' + 'cotton' to 'club, staff')?
2 and 4?