Source : Webster's Revised Unabridged Dictionary (1913)

Custodian \Cus*to"di*an\ (k?s-t?"d?-an), n. [From {Custody}.]
   One who has care or custody, as of some public building; a
   keeper or superintendent.

Source : WordNet®

custodian
     n : one having charge of buildings or grounds or animals [syn: {keeper},
          {steward}]