擂茶 Origin — Dong Chinese Dictionary

léichá

ground tea

léi, lèi rub

Phonosemantic compound. 扌 represents the meaning and 雷 represents the sound.

扌 Meaning component

shou, shǒu hand

扌 is a component form of 手.

雷 Sound component

léi thunder

	Old Chinese
Zhengzhang	ruːl
	ruːls

Phonosemantic compound. 艹 represents the meaning and 余 represents the sound.

艹 Meaning component

cao, cǎo grass

艹 is a component form of 艸.

余 Sound component

yú I

Change in sound

茶 and 余 don't sound similar in modern Mandarin due to historical phonetic changes. They were more similar in Old Chinese.
茶 *lˤra
余 *la

	Middle Chinese	Old Chinese	Gloss
Baxter-Sagart	drae	lˤra	(name of a plant)