Commensalism is a type of symbiotic relationship where one organism benefits without affecting the other organism positively or negatively.
A non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host.
As mentioned before, it's an ecological relationship between two or more organisms from different species living in direct contact with each other.
Neutralism: It describes relationships between two species in which neither species benefits nor is harmed by the other.