The Collaborative International Dictionary of English v.0.48:

Sagathy \Sag"a*thy\, n. [F. sagatis: cf. Sp. sagat['i],
   saet['i].]
   A mixed woven fabric of silk and cotton, or silk and wool;
   sayette; also, a light woolen fabric.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sayette \Sa*yette"\, n. [F. Cf. Say a kind of serge.]
   A mixed stuff, called also sagathy. See Sagathy.
   [1913 Webster]