Translation: The fire was suddenly released out of the third eye.
Explanation: This shloka has been taken from the - third canto of "कुमारसम्भवम्" composed by the great poet Kalidas. This canto describes vividly how Lord Shiva burnt cupid to ashes. This shloka says that being distrubed in his meditation, Lord Shiva got terribly angry and his face looked horrible due to anger. Then he suddenly released fire from his third eye whose flames rose upwards.
Lord Shiva was a great celebrate. If he got attracted towards Parvati, he would marry her and their son would become the chief of god's army and would help to assasinate a demon called Tarkasur. With this purspose, motivated by Lord Indra, cupid alongwith his wife Rati and friend Vasant reached the place where Lord Shiva was doing meditation.
Cupid started to disturb Lord Shiva and tried to attract him towards Parvati. When Parvati offered garland to Lord Shiva and stood aside, cupid took aim at him with an arrow called "Sammohan". Seeing this Lord Shiva lost his temper.
His face became horrible. He opened his third eye and fire came out of it with rising flames which burnt cupid to ashes.