Further examples of archaisms are: morn (for morning), eve (for evening), moon (for month), damsel (for girl), errant (for wandering, e. g. errant knights), etc.
Sometimes, an archaic word may undergo a sudden revival. So, the formerly archaic kin (for relatives; one's family) is now current in American usage.
The terms "archaic" and "obsolete" are used more or less indiscriminately by some authors. Others make a distinction between them using the term "obsolete" for words which have completely gone out of use. The Random House Dictionary defines an obsolete word as one "no longer in use, esp. out of use for at least a century", whereas an archaism is referred to as "current in an earlier time but rare in present usage". 
It should be pointed out that the borderline between "obsolete" and "archaic" is vague and uncertain, and in many cases it is difficult to decide to which of the groups this or that word belongs.
There is a further term for words which are no longer in use: historisms. By this we mean words denoting objects and phenomena which are, things of the past and no longer exist.
Hundreds of thousands of words belong to special scientific, professional or trade terminological systems and are not used or even understood by people outside the particular speciality. Every field of modern activity has its specialised vocabulary. There is a special medical vocabulary, and similarly special terminologies for psychology, botany, music, linguistics, teaching methods and many others.
Term, as traditionally understood, is a word or a word-group which is specifically employed by a particular branch of science,