180. FORMATION is the process by which stems are formed from roots or
from other stems.
181. A word containing a single stem is called a _Simple_ word: as,
#magnus#, _great_, stem #magno-#; #animus#, _soul_, stem #animo-#. A
word containing two or more stems is called a _Compound_ word: as,
#magnanimus#, _great-souled_, stem #magnanimo-#.
182. Most inflected words consist of two parts: a stem, which is usually
a modified root (195), and an inflection ending: thus, in #ductōrī#,
_for a leader_, the root is #duc-#, _lead_, the stem is #ductōr-#,
_leader_, and #-ī# is the inflection ending, meaning _for_.