The Collaborative International Dictionary of English v.0.48:

Ramtil \Ram"til\ (r[a^]m"t[i^]l), n. [Bengali ram-til.]
   A tropical African asteraceous shrub (Guizotia abyssinica)
   cultivated for its seeds (called ramtil seeds or niger
   seeds) which yield a valuable oil used for food and as an
   illuminant.
   [Webster 1913 Suppl.]