keep within (something or some place)
1. To remain inside of something or the boundaries of some physical area. We are asking all visitors to please keep within the marked area. The animals are trained to keep within the yard.
2. To cause or instruct someone or an animal to remain inside of something or such a boundary. In this usage, a noun or pronoun is used between "keep" and "within." Please keep your dogs within the fenced area while the work is being done. You'll have to keep the students within the school until the tornado warning has been lifted.
3. To store something inside of something or some place. In this usage, a noun or pronoun is used between "keep" and "within." Often used in passive constructions. Please ensure that no valuables are kept within the lockers overnight. Records of all such incidents are kept within the company's computer files indefinitely.
4. To not exceed the limits, extent, or scope of some parameter, such as time, budget, law, etc. I don't know how we're going to keep within budget without firing one of our staff members. Please keep within the guidelines I gave you. It doesn't look like they'll be able to keep within the deadline.
5. To ensure that someone or something remains within such a parameter. Local lawmakers want to keep the case within their jurisdiction instead of making it a federal issue. You'll have to learn to keep your spending within the limits of your salary.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
keep within something
to remain within a thing or within the boundaries of something. If you keep within the tourist area, you will be safe. Please keep within the yard.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.