thin slice; slicing thin
Refers to both the act of slicing something thinly and the resulting thin slices, especially in cooking.
Slice the meat thinly and put it in the pot.
Put thin slices of ham in the sandwich.
薄切り is a native Japanese noun for a thin slice of food, while スライス is the loanword used the same way, often as a suru-verb.
Compound of 薄 (usu-, 'thin') + 切り (kiri, 'cutting'), from the verb 切る (kiru, 'to cut').