n.
Function: preposition
Date: 12th century
1 ― used as a function word to indicate enclosure or containment
2 ― used as a function word to indicate situation or circumstance in the limits or compass of: as a : before the end of <gone within a week> b (1) : not beyond the quantity, degree, or limitations of <live within your income> (2) : in or into the scope or sphere of < within the jurisdiction of the state> (3) : in or into the range of < within reach> < within sight> (4) ― used as a function word to indicate a specified difference or margin <came within two points of a perfect mark> < within a mile of the town>
3 : to the inside of : INTO <sunk the sea within the earth ― Shakespeare>