drip, dribble, trickle
涿 centers on liquid moving in small, slow amounts: dripping, dribbling, or trickling.
涿 combines 氵 (water) with 豖, which likely contributes the sound and may relate to a pig or animal, but the exact historical development is uncertain.
Water 氵 beside 豖, a shape that suggests a pig or animal. Picture water dripping slowly from a pig's snout or dribbling as it drinks.
For トク, imagine a single drop of water making a soft 'tock' sound as it hits the ground: tock -> トク, and the drip trickles down.
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