What it is and where it comes from
Lard is fat from pigs, melted and cleaned. The Quran forbids the pig (2:173, 5:3, 6:145), and its fat is included by all scholars.
Where you find it
Pastry and pie crusts, traditional bread and biscuits, tortillas, refried beans, tamales, some Christmas baking, and frying in some restaurants.
What to look for on the label
Look for lard, pork fat, or animal fat without a named animal. Bakery and street food often has no label: ask.
This is a guide, not a fatwa. Recipes change, so check the label, look for halal certification, and ask your local imam where scholars differ.