"Order the day" is an idiom that means something has become or is expected to become the most important topic or task of the day. Synonyms for this phrase include "prevail," "dominate," "rule," "reign," "hold sway," and "be the norm." Other related phrases that convey a similar meaning include "set the tone," "call the shots," "take center stage," and "be the focus of attention." These phrases imply that the highlighted topic or task is the most pressing matter at present and should be given priority over other things. It is essential to have a clear understanding of these idioms and their synonyms to effectively convey meaning and communicate efficiently.