folios
No
I think you mean high folio lap. Individual forms or signatures are folded slightly off centre which leaves one side shorter than the other, the overlapping side is called the lap, depending if the form is face up or down determines wether it has a high folio or low folio lap.
There is no plural form. Do and Do not are verbs
The plural form of him, her, or it is them. (objective pronouns)
Bridges is the plural form of bridge.
The plural form of "is" is "are."
The plural form of "I" is "we."
The plural form of "was" is "were."
"Groceries" is the plural form of "grocery."
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.
The plural form of mouth is mouths. The plural form of month is months. The Mounth is a range of hills in Scotland and does not have a plural form.
The plural form of the demonstrative pronoun 'that' is those.