Two is a noun when it refers to the number two as in two plus two is four Putting two and two together, they came up with the murderer. The word two is derived from the old english words twā (feminine), tū (neuter), and twēġen (masculine, which survives today in the form twain).
The meaning of two is being one more than one in number Idioms put two and two together, to reach the correct and obvious conclusion How to use two in a sentence.
Idioms of two minds (about something) someone's two cents two sides of the same coin (definition of two from the cambridge academic content dictionary © cambridge university press) In two, into two separate parts, as halves Put two and two together, to reach the correct and obvious conclusion. Idioms in two, into two separate parts, as halves
The cake was cut in two