Copy fitting is a complete other beast. It is the process used to determining how much space a given text will occupy in a given set of type specifications. In this digital time, copy fitting is rarely practiced. "Fitting" [matching shapes and spacing of adjacent glyphs while designing a font--or determining how glyphs will be spaced when next to eachother] may be a word used more in the UK or Australia than it is in the USA.
Extended is a term understood by older typographers. "Wide" seems more descriptive and likely to be literally understood better by a broader audience. "Extended" can mean more languages included to some people.