The Chidushei HaRim explains that the reason Shavuos is called Z’man ‘Matan’ Toraseinu and not Z’man ‘Kabbalas’ Toraseinu is that it’s the day that the Torah was ‘gifted’ (?? ????????) to us, and not the day that we ‘received’ the Torah. The gift began on that date–and the actual *receipt* of the gift continues to take place daily –day after day, every time we learn we learn another pasuk, another perek, another daf, even another word of Torah…
This also explains why ?????? doesn’t have a date in the Torah as other holidays do (count 7 full weeks…), that we receive the Torah daily…