What does alnage mean?
The definition of alnage
Al”nage, n.,
Etym: [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.