名詞 i.v.:

1. the cardinal number that is the sum of three and one
   同義詞：four, 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, foursome, Little Joe
2. administration of nutrients through a vein
   同義詞：intravenous feeding, IV

形容詞 i.v.:

1. being one more than three
   同義詞：four, 4, iv