In chemistry, an ionic bond is a connection between two ions with opposite charges. When a positive and a negative ion form a chemical bond, it's an ionic bond.
You're likely to come across the term ionic bond in chemistry class. It's the bond that's formed during the process of one atom losing an electron — becoming negatively charged — and another gaining an electron — becoming positively charged. This is also known as an electrovalent bond or an electrostatic bond. The adjective ionic comes from the noun ion, an electrically charged atom, which means "go" in Greek.