资料来源 : pyDict

在…之上

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Onto \On"to\, prep. [On + to. Cf. {Into}.]
   On the top of; upon; on. See {On to}, under {On}, prep.

资料来源 : Free On-Line Dictionary of Computing

onto
     
        {surjection}