Lord Shiva having eyes with odd number. Lord Shiva has three eyes therefore he is called त्रिनेत्रः or त्रिलोचनः His third eye (which possesses Knowledge) is in his forehead. Two, four etc. are called even numbers while one, there etc. are called odd number. Generally, most of the creatures possess two eyes so a human being can be called युग्मनेत्रः but Lord Shiva possesses three eyes therefore he is called अयुग्मनेत्र, त्रिनेत्र, त्रिलोचन and त्रयम्बकः Whenever Lord Shiva gets angry, fire is released from his third eye and the person or things in front of him is burnt to ashes.