What is the meaning of 'like' in [nothing like]?

Life at college where I enrolled in the modern art course was nothing like I expected.

My understanding is 'like' in both below sentences are same meaning with the above one.

a. At last he saw something in the darkness that looked like two balls of fire.

b. There is something child-like about Marry; she always seems so innocent.

Am I correct?

How about "similar to"?

Basically, it is a comparison. You're comparing if two things are similar. In the first sentence, you're comparing the life that you experienced against your expectations and they turned out to be very much different.

In the dark, he something that looked similar to two balls of fire.

Mary is very innocent. Her behavior is similar to that of a child.

Hope this helps. NS