Very apparent, something that is obvious but unseen or unnoticed by someone. Something that seemingly everyone knows with an exception of one person. (As first heard on "The Sarah Silverman Program")
When something is very apparent and written all over someones face, yet the person is not aware of the situation (only others around them), they are being a "dotnose".
A "Dotnose Situation" is when a group of people identify a dotnose within the group.
When someone is being a "dotnose", one can inform them by saying "you have a dot on your nose".