「Surround from above, deliberately out-of-reach」「roofed pit hole」with「gushing opening」: a view to the outside, or, access to fresher air, early VENTILATION and a WINDOW. Top element is「roofed pit hole」dug into the ground or the side of a hill that were human habitations in the good old days (still today in some regions), over「orifice, enclosure」marked for emphasis on its top side with「gushing air」inside, or, a「net」covering that actually depicts a hole back to the surface other than the door and used as a means of ventilation or as a chimney to vent smoke and/ or inadvertent nocturnal flatulence, or those particularly heavy, difficult to manage odors which do tend to accumulate when the ice box has no ice in August.
For the modern version of this glyph, the original「net」element morphed into a「spread feet, head in crotch」to mean fresh air needed due to naturally smelly or otherwise infected body parts. In some fonts the lower elements continued morphing into「denuded meat」as another item requiring some ventilation if left unrefrigerated for long, or「inverted and extremely spread feet.」After folks moved out of covered pits as a general style for housing, elements became「stench, short leg, curled and dripping」with「appendage spewing venom」in a further reference to the need for the「sweet smell of fresh air.」
The associated modern meaning of「school」is perhaps due to「agitated, hasty, ignorant」students staring out the same WINDOW of a classroom due to tedium, or as the place where students believe「it stinks」and a「funnel」is stuffed into each student's head into which knowledge is poured…viewing the element「hole」while inverted resembles a FUNNEL, with「gushing」from a container of experience, the knowledge of other people, first teaching students how to avoid becoming infected, most likely. SHUTTERS close and protect a window, preventing access while limiting bird strikes and pebbles hurled by the neighbors, from seeing what is beyond, and from seeing what is within.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: shutter; window
Japanese EDRDG: window, pane
Unihan extended: window