Plain Chai necklace in14kt or 18kt yellow, white or rose gold.

Chai (חי) is the Hebrew word for life. The word, consisting of two Hebrew letters —chet (ח) and yud (י)— is a Jewish symbol, frequently appearing on pendants and other jewellery.

Chai also refers to the number 18. That’s because each Hebrew letter has a numerical equivalent, and the sum of chet (numerical value of 8) and yud (numerical value of 10) is 18. As a result of its connection to the word for life, the number 18 is considered a special number in Jewish tradition. For this reason, Jews frequently make gifts or charitable contributions in multiples of $18.

In Hebrew, chai is often referred to in the plural form, chaim (חים), hence the boy’s name Chaim and the toast l’chaim (לחים), which, as anyone who has seen Fiddler on the Roof knows, means “to life.”