-trum

See also: trùm

Latin

Alternative forms

• -culum, -crum, -tra

Etymology

In inherited words, from Proto-Italic *-trom, from Proto-Indo-European *-trom. In words borrowed from Greek (and possibly in some neologisms), from Ancient Greek -τρον (-tron, instrument noun suffix), which is a cognate of the Latin ending. Ultimately from the same source as -culum, -crum, -bulum, -brum, which seem to have originated as contextual variants of a single suffix.

Pronunciation

• (Classical) IPA^(key): /trum/, [t̪rʊ̃ˑ]
• (modern Italianate Ecclesiastical) IPA^(key): /trum/, [t̪rum]

Suffix

-trum n (genitive -trī); second declension

1. forming instrument nouns

Usage notes

During the time when Latin was a living language, this ending seems to have been less productive than the instrument noun suffix -culum (etymologically the same suffix). Weiss 2009, citing Serbat 1975, describes -trum as moribund and unproductive after the time of Augustus; Owens 2016, citing Mir 1984, likewise characterizes -trum as unproductive and "archaic even in the classical period". In native Latin formations, -trum generally can be found only in the following two circumstances:

• when the directly preceding sound is /s/. (The instrument noun suffix -culum seems not to occur in this context.) Examples: mōnstrum, castrum, haustrum.
• when the stem contains /r/ or /l/ (in any position). Examples: mulctrum, rutrum. The use of -trum in this context seems to be a feature of old formations inherited from Proto-Indo-European (such as arātrum, from Proto-Indo-European *h₂érh₃trom). However, -trum is not obligatory in this context: the suffix -culum may be found after /r/, and -crum (a dissimilated variant of -culum) may be found after /l/. Instrument nouns in (...)r...culum or (...)l...crum may represent more recent formations than those in (...)l/r...trum.

The corresponding Ancient Greek ending -τρον (-tron) enjoyed a wider use, and some Greek words with this ending were adapted in ancient times as Latin words ending in -trum, such as scēptrum (from Greek σκῆπτρον (skêptron)) and metrum (from Greek μέτρον (métron)).

In addition, the ending -trum has occasionally been used to derive neologisms from Latin roots outside of the two conditions described above.

• The earliest example of this may be the word spectrum, from speciō, first attested in antiquity in a pair of letters between Cicero and Cassius Longinus, where it is implied that Catius may have created the word as a translation of the Greek philosophical term εἴδωλον (eídōlon).
• In New Latin, -trum has regained some productivity and popularity as a means of forming neuter instrument nouns, apparently influenced by analogy with the masculine agent noun suffix -tor and the way that suffixes descended from it are used in certain modern languages to form inanimate nouns. For example, the New Latin terms computātrum and ōrdinātrum have been coined for 'computer' by partial analogy with words such as Spanish computador and French ordinateur. Other New Latin coinages in -trum include mōtrum and monitrum, adapted from corresponding words in modern languages such as English motor and monitor. In effect, -trum is treated by some New Latin authors as a neuter version of the agent noun suffix -tor, similar to how -trīx serves as its feminine equivalent (despite the fact that in classical Latin, masculine agent nouns in -tor only rarely have a corresponding neuter noun in -trum).

Declension

Second-declension noun (neuter).

Case	Singular	Plural
Nominative	-trum	-tra
Genitive	-trī	-trōrum
Dative	-trō	-trīs
Accusative	-trum	-tra
Ablative	-trō	-trīs
Vocative	-trum	-tra

Derived terms

Latin terms suffixed with -trum