Synonyms: sui generis
Definition: constituting a class of its own; unique
Usage: a history book sui generis; sui generis works like Mary Chestnut's Civil War diary
Similar words: single
Definition: existing alone or consisting of one entity or part or aspect or individual
Usage: upon the hill stood a single tower; had but a single thought which was to escape; a single survivor; a single serving; a single lens; a single thickness