From WordNet (r) 3.0 (2006):
iv
adj 1: being one more than three [syn: four, 4, iv]
n 1: the cardinal number that is the sum of three and one [syn:
four, 4, IV, tetrad, quatern, quaternion,
quaternary, quaternity, quartet, quadruplet,
foursome, Little Joe]
2: administration of nutrients through a vein [syn: intravenous
feeding, IV]