nothing is no thing, denoting the absence of something. Nothing is a pronoun associated with nothingness.
In nontechnical uses, nothing denotes things lacking importance, interest, value, relevance, or significance. Nothingness is the state of being nothing , the state of nonexistence of anything, or the property of having nothing.
The understanding of 'nothing' varies widely between cultures, especially between Western and Eastern cultures and philosophical traditions. For instance, Śūnyatā (emptiness), unlike "nothingness", is considered to be a state of mind in some forms of Buddhism (see Nirvana, mu, and Bodhi). Achieving 'nothing' as a state of mind in this tradition allows one to be totally focused on a thought or activity at a level of intensity that they would not be able to achieve if they were consciously thinking.
A classic example of this is an archer attempting to erase the mind and clear the thoughts to better focus on the shot. Some authors have pointed to similarities between the Buddhist conception of nothingness and the ideas of Martin Heidegger and existentialists like Sartre, although this connection has not been explicitly made by the philosophers themselves.
In some Eastern philosophies, the concept of "nothingness" is characterized by an egoless state of being in which one fully realizes one's own small part in the cosmos.
The Kyoto school handles the concept of nothingness as well.
Taoism's "Nothingness" vs Buddhism's "Emptiness"
There are similarities and differeneces between Taoism's "Nothingness" (无) vs Buddhism's "Emptiness" (空). Both "Nothingnesss" and "Emptiness" are not simply referring to the absence of physical things.
It is about the realization of the "being" of one self and the universe. Taoism and Buddhism believe that the universe is created or originated from "Nothingness" or "Emptiness". It is interesting that the modern science also proposed that there is "nothing" before the creation of universe. ie. Before time and space exist, there is "nothing".