Place restrictions on is a phrase that means to impose rules or regulations on something. It is often used in the context of setting boundaries or limits on certain activities or behaviors. For example, a government might place restrictions on the sale of certain goods or services, or an employer might place restrictions on the hours an employee can work. In the context of the crossword puzzle, the answer to the clue 'LIMIT' is 'LIMIT', which is a five-letter word that fits the definition of the phrase 'place restrictions on'.