brown-bag      
 adjective [ before noun ] uk/ˌbraʊnˈbæɡ/ us/ˌbraʊnˈbæɡ/
brown-bag lunch 自带的午餐
food that you take to work with you to eat for your meal in the middle of the day
  There are as many brown-bag lunches eaten today as lunches in restaurants. 现在自带午餐的人和在餐馆里吃午餐的一样多。 
 Once a month, we gather for a brown-bag lunch in the local park.
 The next time you want something a bit different for a brown-bag lunch, why not try one of these tasty recipes?
 Office workers eat their brown-bag lunches while enjoying the music.
 Remember that you can save a few dollars every day by taking a brown-bag lunch to work.
 brown-bag       
verb [ I or T ] US uk/ˌbraʊnˈbæɡ/ us/ˌbraʊnˈbæɡ/
 (通常放在牛皮纸袋里的)自带午餐
to take your own food to eat during the day, usually in a brown paper bag
  The park has become a place where office workers brown-bag it and take leisurely strolls. 公园成为办公室职员在那里吃自带午餐,然后悠闲散步的地方。