A Non-deterministic Finite Automaton (NFA) is a theoretical model used in computer science to represent and analyze the behavior of certain types of computational systems. Unlike deterministic finite automata (DFAs), NFAs can have multiple possible transitions for a given input symbol, including transitions to multiple states or even no transition at all. This means that for a single input string, an NFA can explore many different paths simultaneously. NFAs are particularly useful in the field of formal languages and automata theory, as they can be used to recognize patterns and describe regular languages. Although NFAs may seem more complex, they are equivalent in power to DFAs, meaning any language recognized by an NFA can also be recognized by a DFA.