There is a big difference between Shiva and Shankar as Shiva is the supreme soul/Nirakar where as Shankar is the deity. Again everything depends upon you (Bhakta) that what is your devotion level because in a rough view, you can say that both are same because shiva is the name of almighty who has no form (formless), beyond one’s thought, one can’t describe fully, however Shankar is called as the human awatar of Shiva. The Shankar is considered as the “Adiyogi – The first Yogi” who has given the “Yoga” to the world.
The Shiva means – Auspicious One. He is the supreme god who is omnipresent and people call him with different names. The shiva is worshipped in “Linga” Form. Actually the word “Linga” literally means Symobol, Sign or Mark. For example, People say “Nancy is Strilinga” that means Nancy name is used for female. Again, if you go to south India, people use names as “Ramalingam” that means Something like Rama. The Shivalingam is a oval or egg-shaped form that is really helpful for people who are seekers (Sadhak.) They were getting difficulties to concentrate the actual form of God which can’t be sketched. The shape of linga helps spiritual people concentrate and do meditation in best possible way so this is the reason Rishis call it “Dhyan Linga”. When you go for meditation, you need to put your concentration towards the Almighty. Since he is beyond the concept of human forms, Lingam is something that is helpful to represent him somehow logically and scientifically. The Lingam is supposed as The Infinite Pillar of Light.
The three lines used on shivalinga symbolizes his triple characteristics of Trimurti, Trilokinath – The almighty of all three worlds, Trikaldarshi – The one who sees the three aspects of time. He is also called as Swayambhu, Ajanma and Sada Shiva – The one who is eternal and there is no creator above him. Om Namah Shivaya!
Share Your Thought about Shiva/Shankar in the comment section to help users know more. Thanks.