This is the definition of bittersweet.

Raul Candy Store has been feeding Alphabet City’s sweet tooth at 205 Avenue B since 1981, but the shop’s owner, Raul Santiago, 75, is finally throwing in the taffy on Feb. 28.

“Now that he’s leaving, everybody is coming to say their goodbyes and pay their respects,” Jennifer Nieves, a longtime regular who thinks of Santiago as a father, tells The Post. She says Santiago has never taken a vacation.

But unlike other shuttered storefronts in the area, the decision to close wasn’t spurred by skyrocketing rent costs. Raul and his wife are simply looking to retire, PIX 11 reports.

Many customers have been returning to the store in tears, says Nieves, 45, recalling the Christmas dinners, special Halloween candy, summertime barbecues and domino games that defined the beloved shop, which actually has held court at different locations in the neighborhood for nearly 43 years.

On Thursday, the final incarnation of Raul Candy Store will be open from 5:30 a.m. till late at night, and all remaining candy will be free.

While its iconic cherry candy, dispensed from a lipstick-like container, sold out last week, an array of sour and caramel sweets remain. The coffee, usually just 50 cents, will be free as well.