Source : Webster's Revised Unabridged Dictionary (1913)

Knawel \Knaw"el\, n. [Akin to G. knauelk, kn["a]uel,prop., a
   ball of thread, coil. Cf. {Clew}.] (Bot.)
   A low, spreading weed ({Scleranthus annuus}), common in sandy
   soil.

Source : WordNet®

knawel
     n : widely distributed low-growing Eurasian herb having narrow
         leaves and inconspicuous green flowers [syn: {knawe}, {Scleranthus
         annuus}]