^boiled linseed oil, yes: it's a varnish for wood (outdoor use and tool handles, mostly).
RAW linseed oil is another kettle of fish (mixing metaphors), used for oil painting as well as an ingredient in many concoctions. I haven't knowingly used raw linseed oil on leather, but maybe I have in shoe polish or creme and didn't know.
edit: I must correct myself (again!) raw linseed oil is also used as a wood finish but it's considered a very slow-drying oil and provides a softer finish than boiled oil, once dried (or cured). Raw linseed oil is used on leather, but I personally would not make it my first choice.