Of such words, however, all are not equally to be considered as parts of
our language; for some of them are naturalized and incorporated; but
others still continue aliens, and are rather auxiliaries than subjects.
This naturalization is produced either by an admission into common
speech, in some metaphorical signification, which is the acquisition of
a kind of property among us; as we say, the _zenith_ of advancement, the
_meridian_ of life, the _cynosure_[2] of neighbouring eyes; or it is the
consequence of long intermixture and frequent use, by which the ear is
accustomed to the sound of words, till their original is forgotten, as
in _equator, satellites_; or of the change of a foreign to an
English termination, and a conformity to the laws of the speech into
which they are adopted; as in _category, cachexy, peripneumony_.

Of those which still continue in the state of aliens, and have made no
approaches towards assimilation, some seem necessary to be retained,
because the purchasers of the Dictionary will expect to find them. Such
are many words in the common law, as _capias, habeas corpus,
praemunire, nisi prius_: such are some terms of controversial
divinity, as _hypostasis_; and of physick, as the names of
diseases; and, in general, all terms which can be found in books not
written professedly upon particular arts, or can be supposed necessary
to those who do not regularly study them. Thus, when a reader not
skilled in physick happens in Milton upon this line,

--pining atrophy,
Marasmus, and wide-wasting pestilence,

he will, with equal expectation, look into his dictionary for the word
_marasmus_, as for _atrophy_, or _pestilence_; and will
have reason to complain if he does not find it.