It stands for contra midpoint only; a non-displayed order type that is priced at the midpoint between the best bid...

A contra midpoint only (CMO) that comes with “post-only” functionality which allows the order, similar to a midpoint peg post-only...

A contra midpoint only (CMO) that comes with “post-only” functionality which allows the order, similar to a midpoint peg post-only...

It stands for contra midpoint only; a non-displayed order type that is priced at the midpoint between the best bid...

A non-displayed order type that is priced at the midpoint between the best bid and the best offer (e.g., NBBO)....