From Longman Dictionary of Contemporary Englishkeep somebody/something ↔ down phrasal verb1PREVENTto prevent the size, cost, or quantity of something from increasing or being too greatWe need to keep costs down.2SICK/VOMITto succeed in keeping food in your stomach, instead of bringing it up again out of your mouth, when you are illI could hardly keep anything down for about three days.3used to ask someone to make less noiseKeep your voice down – she’ll hear you!Can you keep it down – I’m trying to work.4to prevent a group of people from becoming as successful and powerful as the other people in a societyPlantation owners kept slaves down by refusing them an education. →keep→ See Verb table
Examples from the Corpus
keep down• For most people a good book is a necessity when travelling, choose a paperback to keep the weight down.• He was all in favour of anything that kept their costs down.• Pete and Chrissie's baby couldn't keep its food down.• The turbocharger is water cooled and its vanes are small to keep inertia down.• You lose their attention if you keep staring down at the papers in your hand.• She forgot the excitement down below, she forgot the misunderstanding that had kept them silent down the gulch.• He kept his head down under fire, avoidedtrouble, trusted in luck to keep him alive.• Although the blownrubberkeeps there weight down, wear patterns after 300 and 400 miles seem to bear out this view.keep it down• Stevens brought Sierra Leone down, Taylor keeps it down.• A lump came to my throat and I had to eat something to keep it down.• Can you girlskeep it down?• Some one in the next room shrieked at her to keep it down.• You oughta learn to keep it down, boy.• I can't keep it down here with my wife and children.• May I keep it down here?• Keep it down! I'm trying to talk on the phone!• Hey you guys - keep it down, or Mom'll hear!• Some said she was obsessed with her weight and determined to keep it down to under six stones.• Keep it down, will you? We're trying to sleep.