"Sack lunch" is a term that has been used for decades, but it can get repetitive and mundane. Here are some synonyms: brown bag lunch, packed lunch, grab-and-go lunch, picnic lunch, lunch box meal, field trip lunch, portable lunch, meal to go, lunchtime treat, bento box lunch, and packable lunch. Each of these terms can add a bit of creativity and excitement to the traditional "sack lunch." With new synonyms to choose from, it might even inspire someone to try new recipes or pack more exciting lunch options. Whatever term you use, the most important thing is to have a delicious and nutritious lunch that will give you the energy to tackle the rest of your day.