Tri means three and Shool means a thorn. Trishul is the weapon of Shiva Ji. There are three hindrances, the thorns in our lives.
Adibhautika
Adidaivika
Adhyatmika
Man
Buddhi
Ahankaar
Satva
Rajas
Tamas
We have conceived these triplets as the inevitable parts of our lives. Attachment, greed, jealousy, etc are included in this classification. These are the thorns, which we acquire from the world and, skewer our lives. Then, we yell over our pains. We are the reason behind all the thorns. Thus, it is inevitable to remember the Self 24/7.