The Collaborative International Dictionary of English v.0.48:

Rushlight \Rush"light`\, n.
   A rush candle, or its light; hence, a small, feeble light.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rushlight
    n 1: a tallow candle with a rush stem as the wick [syn:
         rushlight, rush candle]