Definition of thirled:
(v) :
(by extension) To bind; to obligate to use or be associated with.
(n) :
(dialectal) A low door in a dry-stone wall to allow sheep to pass through; a smoot.
(n) :
(dialectal or puristic, otherwise archaic) A hole, an aperture, especially a nostril.
(v) :
(transitive, puristic, otherwise obsolete) To pierce; to perforate, penetrate, cut through.
(v) :
(transitive, mining, obsolete) To drill or bore; to cut through, as a partition between one working and another.
(n) :
(mining, obsolete) A long adit in a coalpit.