Vine's Expository Dictionary of NT Words
an adjective, denoting "appointed beforehand" (pro, "before," tithemi, "to put, appoint:" see APPOINT No. 3, Note), is used as a noun, prothesmia (grammatically feminine, with hemera, "a day," understood), as in Greek law, "a day appointed before," Galatians 4:2 , RV, "the term appointed," i.e., "a stipulated date" (AV, "the time appointed").
These files are public domain.
Vines, W. E., M. A. Entry for 'Tent-Makers'. Vine's Expository Dictionary of NT Words. https://www.studylight.org/dictionaries/eng/ved/t/tent-makers.html. 1940.