one of the oldest written words in the english language still in usage -- NOT!

[Mark A. Mandel]

Joshua Nimocks clarifies:

#I'm sorry.  I should have specified: alder, 'the head of a family or
#clan.'

I'm sorry, I don't think that's still in usage.

OED OnLine (diacritics dropped for email):

        >>>
Obs.

    1. Parent, ancestor, elder (chiefly in pl.). [In this sense only in
OE.; superseded by the compar. of the adj. ald (eald), eldran: see
ELDER.]

    2. The head of a family or clan; a patriarch, chief, prince, or
ruler. (Used to translate L. titles, as senior, princeps, dominus, dux.)
        <<<

The latest citation is "c1340". And "alderman" is as opaque as "woman".
Obs., indeed.

-- Mark A. Mandel
   Linguistic Data Consortium, University of Pennsylvania