collect, gather up, pick up
掇 centers on bringing scattered things together by hand: collecting, gathering up, or picking up items.
掇 combines 扌 (hand) with 叕, which likely contributes the sound and the idea of joining or connecting, suggesting gathering things together by hand.
The hand radical 扌 beside 叕 looks like a hand reaching out to collect scattered pieces and gather them up.
For タツ, imagine a hand picking up tacks scattered on the floor: tacks -> タツ, and the hand gathers them all together.