Source : Webster's Revised Unabridged Dictionary (1913)

Tassel \Tas"sel\, v. i. [imp. & p. p. {Tasseled}or {Tasselled};
   p. pr. & vb. n. {Tasseling} or {Tasselling}.]
   To put forth a tassel or flower; as, maize tassels.

Source : WordNet®

tassel
     n : adornment consisting of a bunch of cords fastened at one end
     [also: {tasselling}, {tasselled}]

tasselling
     See {tassel}