Merit itself comes from the same root, though: from the OED entry on merit:
classical Latin meritum due reward, worthiness to receive good or bad treatment, action worthy to receive such treatment, use as noun of neuter of meritus, past participle of merēre, merērī to obtain for one's share, earn as pay, deserve, probably cognate with ancient Greek μείρεσθαι to receive a share (see mero- comb. form1).