The Collaborative International Dictionary of English v.0.48:

Alnage \Al"nage\ ([a^]l"n[asl]j), n., [OF. alnage, aulnage, F.
   aunage, fr. OF. alne ell, of Ger. origin: cf. OHG. elina,
   Goth. aleina, cubit. See Ell.] (O. Eng. Law)
   Measurement (of cloth) by the ell; also, a duty for such
   measurement.
   [1913 Webster]