Can’t we find out when the tide rises by looking online?
The kanji and the word are exactly the same. That means they share meanings as well.
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 to remember: If you think of the tide, you think of the ocean. If you think of the ocean and what it's filled with (besides water) you think of salt (しお).