Trial etymology in English

English word trial comes from Latin tres, Latin -alis

Dictionary entry	Language	Definition
tres	Latin (lat)
-alis	Latin (lat)	Used to form adjectives of relationship from nouns or numerals.
trialis	Latin (lat)
trial	English (en)	(grammar) Pertaining to a language form referring to three of something, like people; contrast singular, dual and plural. (See Ambai language for an example.). Characterized by having three (usually equivalent) components.. Triple.

Trial etymology