A commonly encountered pair of words in academic writing are former and latter. Former refers to the first of two things named (remember that former comes first), while latter refers to the second of two things named (remember that the latter comes later). In the following example, the adjective former means that the author will use the first definition for the Viking Age, that is, 800–1050.

The Viking Age or the Late Iron Age is a rudimentary appellation for the period between 800–1050 AD in Scandinavia. Philologists specialized in runes use a slightly broader spectrum for the Viking Age period, locating the era between 800–1100 AD. In the present thesis, the former chronological definition of the Viking Age will be used.

These words should only be used when distinguishing between two (and no more than two) alternatives.