The term PLACE A MAXIMUM ON can be summarized as 'imposing a LIMIT'. This means that a certain amount or quantity is set as the maximum that can be achieved or attained. This can be used in many different contexts, such as setting a maximum number of people allowed in a room, or setting a maximum budget for a project. The crossword solution for this term is LIMIT, which is a noun meaning 'a restriction on the size, extent, or quantity of something'.