惜 is built from the 忄 (heart (left)) and 昔 components.
It reads セキ like 昔, as do 籍 — learn 昔 once and the family's reading comes with it.
A common word using 惜 is 惜しい (おしい), meaning “regrettable, disappointing”.
Kanji that look similar include 悼, 情, 惨, and 悟.
