n, pl  lu*mi*na  or  lumens  1  :  the cavity of a tubular organ <the of a blood vessel>   2  :  the bore of a tube (as of a hollow needle or catheter)  3  :  a unit of luminous flux equal to the light emitted in a steradian by a uniform point source of one candle intensity .
 
 
 
Similar sounding terms:  lam·i·na  lem·on  li·men  Lym·naea 
 
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