"inner, fibrous bark of the linden tree," Old English bæst, a general Germanic word (cognate with Old Norse, Old Saxon, Middle Dutch, Old High German, German bast) of uncertain origin.
Entries linking to bast
baste v.1
"sew together loosely," c. 1400, from Old French bastir "build, construct, sew up (a garment), baste, make, prepare, arrange" (12c., Modern French bâtir "to build"), probably from Frankish or some other Germanic source, from Proto-Germanic *bastjan "join together with bast" (source also of Old High German besten; see bast).