Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you:
You make lacquer out of uni root sh*t (うるし). You gotta get deep in the uni to the root of its sh*t and rub it into a paste to make the lacquer. Then rub that on wooden stuff! Yay! Uni root sh*t!
If you touch a lacquer leaf you’ll get a rash on your hand.