-plex

See also: plex

English

Borrowed from Latin -plex (“-fold”).

-plex

comprising a number of parts

Disputed.

Possibly from Proto-Italic *-pleks, from Proto-Indo-European *pleḱ- (“to plait, to weave”), making it equivalent to plicō (“to fold”) +‎ -s.
Possibly from Proto-Italic *-plaks, with regular reduction of Proto-Italic *-a- to Latin -e- in a non-initial closed syllable.^[1]
In either case, it may ultimately derive from an extension of Proto-Indo-European *pel- (“to fold”). Compare -plus.

Potential cognates include Umbrian -𐌐𐌋𐌀𐌊 (-plak), found in 𐌕𐌖𐌐𐌋𐌀𐌊 (tuplak), and Ancient Greek -πλαξ (-plax), found in δίπλαξ (díplax) and τρίπλαξ (tríplax).^[2]^[3]

De Vaan 2008 derives Latin -plex from Proto-Italic *-pleks, from the e-grade of the root *pleḱ-, and Greek -πλαξ (-plax) from Proto-Indo-European *-pl̥ḱ-, the zero-grade ablaut variant of the same root. De Vaan considers the meaning and etymology of the Umbrian form to be unclear.^[2] At the same time, De Vaan reconstructs simplex as coming from Proto-Italic *sm̥-plak-s.^[4]
Others accept the Umbrian form as a cognate, which suggests Proto-Italic *-plaks: this complicates the etymology from *pleḱ- (“to plait, to weave”). Flemestad and Olsen 2017 treat all three of duplex, 𐌕𐌖𐌐𐌋𐌀𐌊 (tuplak), and δίπλαξ (díplax) as cognates, and prefer to derive them from the root *pel- (“fold”) combined with a suffix *-ak-.^[5]
Some argue that Greek -πλαξ (-plax) is not from *pleḱ- (“to plait, to weave”), but from an unrelated root found in πλάξ (pláx, “surface”), which van Beek 2022 identifies as coming from *plek‑ (“to strip, flay”).^[6]
Coleman 1992 suggests duplex and 𐌕𐌖𐌐𐌋𐌀𐌊 (tuplak) might be derived from Proto-Indo-European *pleh₂- (“flat”), the root of plānus, which he considers to be an extension of *pel-.^[7]

-plex (genitive -plicis); third-declension one-termination suffix

Third-declension one-termination adjective.

	masc./fem.	neuter	masc./fem.	neuter
	singular		plural
nominative	-plex		-plicēs	-plicia
genitive	-plicis		-plicium
dative	-plicī		-plicibus
accusative	-plicem	-plex	-plicīs -plicēs	-plicia
ablative	-plicī -plice		-plicibus
vocative	-plex		-plicēs	-plicia

^ Kent, Roland G. (1932), “The Sounds of Latin. A Descriptive and Historical Phonology”, in Language, volume 8, number 3, →JSTOR, page 103
↑ ^2.0 ^2.1 De Vaan, Michiel (2008), “-plex”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 473
^ Beekes, Robert S. P. (2010), “δίπλαξ, -κος”, in Etymological Dictionary of Greek (Leiden Indo-European Etymological Dictionary Series; 10), with the assistance of Lucien van Beek, Leiden, Boston: Brill, →ISBN, page 338
^ De Vaan, Michiel (2008), “-sem-, sim-”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 553
^ Flemestad, Peder; Olsen, Birgit Anette (2017), “Sabellic Textile Terminology”, in Textile Terminologies from the Orient to the Mediterranean and Europe, 1000 BC to 1000 AD, →DOI, page 219
^ Lucien van Beek (2022), “Chapter 10 The Reflexes of *l̥”, in The Reflexes of Syllabic Liquids in Ancient Greek‎^[1], Leiden, The Netherlands: Brill, →ISBN
^ Coleman, Robert (1992), “Chapter 12: Italic”, in Jadranka Gvozdanović, editor, Indo-European Numerals, Mouton de Gruyter, page 423