Complex sentence: In QFT this combination of fields is called the vacuum state, it's associated zero-point energy is called the vacuum energy and the expectation value of the Hamiltonian is called the vacuum expectation value.
Split into simpler sentences: In QFT this combination of fields is called the vacuum state and it's associated zero-point energy is called the vacuum energy. The expectation value of the Hamiltonian is called the vacuum expectation value.