4

Từ điển WordNet v3.1 - WordNet Dictionary

I - noun

the cardinal number that is the sum of three and one (Freq. 13)
• Syn:
four, IV, tetrad, quatern, quaternion,
quaternary, quaternity, quartet, quadruplet, foursome, Little Joe
• Hypernyms:
digit, figure

II - adjective

being one more than three (Freq. 51)
• Syn:
four, iv
• Similar to:
cardinal