[191]. Verbs in -ēre, and those in -āre and -īre in which the ā or ī is confined to the present system ([868], [874]) usually have parallel nouns formed directly from a root: as,

doc-tor, teacher, doc-umentum, lesson, doc-ilis, teachable (√doc-, docēre); sec-tor, cutter (√sec-, secāre); dom-itor, tamer, dom-inus, master, dom-itus, tamed (√dom-, domāre); sarc-ina, package (√sarc-, sarcīre).

[192]. But a noun is sometimes exceptionally formed from the present stem of a verb in -ēre: as, monē-ta, mint (monēre); acē-tum, vinegar (acēre); virē-tum, a green (virēre); suādē-la, persuasion (suādēre); habē-na, rein (habēre); egē-nus, needy (egēre); verē-cundus, shamefast (verērī); valē-tūdō, health (valēre).

[193]. Verbs in -ere, and particularly such as have a present in -nō, -scō, -tō or -iō ([832]), usually have their parallel nouns formed directly from a root: as,

vic-tor, conqueror (√vic-, vincere); incrē-mentum, growth (√crē-, crēscere); pul-sus, a push (√pol-, pellere).

[194]. Sometimes, however, nouns are formed from such verb stems, and not from roots: as, lecti-stern-ium, a couch-spreading (sternere, √ster-, strā-); vinc-ibilis, conquerable (vincere, √vīc-); pāsc-uum, pasture (pāscere, √pā-); pect-en, comb (pectere, √pec-); fall-āx, deceitful (fallere, √fal-).

[STEMS.]

[195]. A Stem is that part of a word which contains its meaning, and is either a root alone or more commonly a root with an addition called a Formative Suffix.

Thus, in the word ducis, leader’s, the stem, which is identical with the root duc-, means leader; a root thus serving as a stem is called a Root Stem; in ductōris, leader’s, the stem is formed by the formative suffix -tōr-, denoting the agent, attached to the √duc-.

[196]. New stems are formed by adding a suffix to a stem. Thus, from ōrātōr-, speaker, is formed by the addition of the suffix -io-, a new stem ōrātōr-io-, N. ōrātōrius, speaker’s.