A codon is the triplet sequence in the messenger RNA (mRNA) transcript which specifies a corresponding amino acid (or a start or stop command). An anticodon is the corresponding triplet sequence on the transfer RNA (tRNA) which brings in the specific amino acid to the ribosome during translation. The anticodon is complementary to the codon, that is, if the codon is AUU, then the anticodon is UAA. There are no T (Thymine) nitrogen bases in mRNA. It's replaced by U (Uracil).
