What is what does too mean?

The word "too" is an adverb that is used to convey the sense of something that is excessive or beyond what is required or acceptable. It can also mean in addition or also.

For example:

• "There are too many people in this room. It's overcrowded." (indicating excess)
• "I want to come too." (indicating addition or also)

In some cases, "too" can also be used as an adjective to mean extremely or excessively, as in "the water was too cold to swim in."

It is important to note that "too" is often confused with "to" (a preposition indicating direction or movement towards a place or person) and "two" (the number 2).