'trochaic' originates from Greek, ultimately from Late Latin/Medieval Latin forms (e.g. 'trochaeus'), where the Greek element 'troch-'/ 'trochaio-' was used in words describing the trochee metrical pattern.

'trochaic' entered English via Medieval/Modern Latin 'trochaeus' and French 'trochaïque', and became the English adjective 'trochaic' to describe the trochee-based meter.

Initially tied to technical names for the metrical foot (and its Greek/Latin descriptors), over time it came to mean specifically 'of or relating to trochees' or 'in trochaic meter'.