Lo-cal food or drink is made to contain fewer calories than the usual version — less ‘fuel’ in the portion, so it is sold as a lighter choice. You see it on cans, yoghurt, salad dressing, beer, and ‘diet’ lines in a supermarket. It is informal packaging English, a bit advertising-ish, more spoken and commercial than academic. People also write low-cal. Though actually, lo-cal does not automatically mean no sugar, no fat, or ‘healthy in every way’. It only talks about calorie count. A lo-cal biscuit can still be salty, or full of sweeteners, or easy to eat too many of. It is the cousin of labels like lite and diet. Speakers sometimes stretch it to meals (‘I’ll have something lo-cal’) meaning they want a smaller-energy choice, not a brand name. It is not the word local (nearby). The hyphen and the missing w are the hint: lo- stands for low.