תּוֹרָ֥ה צִוָּה־לָ֖נוּ מֹשֶׁ֑ה מוֹרָשָׁ֖ה קְהִלַּ֥ת יַעֲקֹֽב׃
모세가 우리에게 율법을 명하였으니 곧 야곱의 총회의 기업이로다
Metzudat Zion
Kohelet. This refers to the concept of gathering and collecting, like the congregation of Jacob (Deuteronomy 33:4), and King Solomon was referred to [as Kohelet], because he gathered the conflicting opinions to merge and clarify the correct from the incorrect:
Rashi
Koheles. [He was called Koheles] because he gathered [=קִהֵל much wisdom,11The term קהלת meaning gathering is in Devarim 33:4 where it states, “the gathering [קהלת] of Yaakov.” (Metsudas Tzion) and similarly, elsewhere [Scripture] calls him, “Agur Bin Yokeh,”12Mishlei 30:1. This is a reference to Shlomo, meaning the gatherer [אגור] of wisdom [בן] spewed out [יקה] the prophecy [המשא]. because he gathered אָגַר all the wisdom and spewed וַהֲקִיאָהּ it out, and some say that he would say all his words in public assembly [=בְּהַקְהֵל.13Alternatively, he gathered together and clarified many conflicting views. (Metsudas Tzion)