The phrase "defence budget" refers to the amount of money allocated by a country or organization to spend on its military and armed forces. Full definition
We can not cut just 50 billion from defence budget, but it is alright to cut from education and make school for 4 days. (politicalticker.blogs.cnn.com)
But we have just exposed them as committed to a massive # 53 billion of extra spending - more than the total defence budget. (politics.co.uk)